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This programme contains scenes which
some viewers may find upsetting.


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00:00:08,560 --> 00:00:10,280
Sex.


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A simple word for the most intimate,
sensitive and complex of subjects.


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Sex is at the core of our deepest
relationships.


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It's part of what makes us human -
it drives our passions,


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our frustrations and our moments
of greatest ecstasy.


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One way or another it defines us.


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But unravelling the secrets of sex


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has been a contentious
and risky business for science...


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..and an equally big challenge
for television.


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For more than 45 years,
Horizon and the BBC


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have reported on how science has
improved our understanding of sex,


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strived to solve our problems
with it,


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and even tried to help us
do it better.


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In this programme we'll also
look at how science helped us


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understand gender and fertility.


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But can science really save the day
when sex goes wrong?


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Biologically, of course,
sex is about reproduction,


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but that falls rather short of
what it means to us as a species.


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Arousal, desire, sexuality,
fertility


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are all incredibly personal
to each of us.


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And because of that,


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science got involved in our
sex lives rather late in the day.


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Until recently, we knew very little


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about the most basic aspects
of human sexuality.


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So how did scientists
uncover our sexual secrets


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and what did they learn?


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To truly understand a subject
so complex, delicate


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and sometimes plain embarrassing,


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someone needed to ask difficult
and intimate questions


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about what we got up to
behind closed doors.


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Perhaps the first person
to approach sex


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in a systematic and scientific way
was Dr Alfred Kinsey.


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Kinsey's lifelong passion
was collecting insects.


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But in the 1930s
he switched his attention


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to collecting the sexual habits
of humans.


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When asked by the bright young
students of Indiana University


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to teach a course that covered
human sexual behaviour,


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Kinsey discovered that very little
research had been carried out


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on the sexual habits of people.


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We knew far more about copulation in
other animals than we did in humans.


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I discovered that there is
practically nothing known


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about human sexual behaviour


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in comparison with what we knew about
the sexual behaviour of other animals


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and in comparison in what we knew
about the activities


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of other parts of the human body.


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In order to get meaningful data
about the sex lives of humans,


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he asked his own students
about their intimate experiences.


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And, for the sake of science,
he pulled no punches.


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He asked me questions about the...


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..dimensions of my sex organs
which I couldn't answer.


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"Well, take this envelope
and this piece of paper,


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"go home and measure yourself
and send it to me."


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Kinsey's curiosity became obsession.


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In less than ten years
he personally collected


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sexual information
on more than 7,000 people.


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Kinsey's results were published
in two books


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that both became best sellers.


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Sexual Behaviour in the Human Male
appeared in 1948,


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followed by Sexual Behaviour
in the Human Female in 1953.


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For the first time,
science was attempting to obtain


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objective data on what ordinary
people did behind closed doors.


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Don't forget, this was in early days,
when there were a lot of suspicions


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about such things, and in addition
it was the McCarthy era,


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so Kinsey had to be absolutely
circumspect in everything.


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This related to things like dirty
jokes, we were never permitted


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to do such things,
tell such things, on the staff.


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Kinsey's work revealed that
affairs in marriage


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were extremely common
for both men and women.


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But that was the least of it.


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His findings showed that even before
the sexual revolution of the 1960s,


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nearly 50% of women
had premarital sex.


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Amongst 10,000 interviewees,


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92% of men and 65% of women
said that they masturbated.


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Just under half of the women
interviewed


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reported an erotic experience
with another woman.


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And 8% of men and 3% of women


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admitted to some kind of
sexual activity with animals.


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It was clear that the laws governing
sexual activity in America -


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particularly in the more
conservative states -


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were far more restrictive
than the reality


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of many Americans' sex lives.


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He told me,
with an absolutely straight face,


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perhaps just the trace of a smile,


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that what he knew about the laws
of Indiana,


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and what he had learned about
the males of Indiana,


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indicated to him that 85% of us
should be in jail.


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Kinsey's findings were added to
through the decades


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until we had a vivid picture


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of the spectacular variety
of human sexual behaviour.


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But scientists didn't just deal with
behaviour during sex.


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They were interested
in the rules of attraction.


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Males are almost always prepared
for sexual behaviour,


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but females usually run away
from males,


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and that, after all,
creates male interest.


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But when females are receptive
they ensure that, whatever happens,


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they're caught.


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At certain times in her cycle,


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the female will allow herself
to be caught even more readily.


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The male may appear as a mere toy


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in the hands of
a manipulative female,


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but it's probable that each
is influenced by hormones.


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More than 30 years on,


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the role of female hormones in
influencing sexual desirability


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is still being investigated.


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A group of scientists
recently decided


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to conduct a most unusual experiment
in a most unusual place.


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They recruited 18 lap dancers


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and asked them to keep detailed
records over two months


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of how much they earned every night
in tips.


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They also asked the dancers
to record data


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about their menstrual cycles.


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Looking at how earnings
varied over their monthly cycle,


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they discovered something
remarkable.


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During six days around the middle of
their monthly cycle,


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when the dancers would have been
at their most fertile,


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they were earning an average
of around 70 an hour.


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In the rest of the month
they earned just 45 an hour.


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If money talks, this suggests


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that male clients found the dancers
far more attractive


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when they were
at their most fertile.


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The men may have been responding to
chemical or physical signals


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that the women were
unconsciously producing.


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Understanding what turns us on
is one thing,


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but scientists wanted to find out
about the physiology of sex.


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In the 1950s, two researchers
opened the bedroom door


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in an attempt to quantify exactly
what happened to the human body


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before, during and after sex.


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The films they made
as part of their research


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still make for uncomfortable
viewing.


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In a physiology laboratory,
you have to have means...


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create means and measures of
evaluating response.


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We needed to know heart rate,


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body temperatures,
skin changes...so on.


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And we're the first to say
that our work was primitive.


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In 1958, William Masters and
Virginia Johnson made this film


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of volunteers in their laboratory
having sex


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and becoming sexually aroused
through masturbation.


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The areolae begin to swell,


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the entire breast shows
increase in size.


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Unsurprisingly,
their work was controversial,


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but they made an effort to be
as objective as possible


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in the way they collected
and reported their findings.


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We did everything to take out the
titillation in those early times.


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We kept a very low profile,
and yet a very strong one


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within the research and medical,
scientific community,


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but they still find it
very discomforting


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to think about the means, which is
someone in a laboratory,


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someone under lights,
someone wired up.


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Even though there's a lot of that
going on


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at every other kind of research
under the sun...


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when it's sex, it's different.


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From the 1950s onwards, scientists
continued to investigate sex,


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building on the work of
Masters and Johnson


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and delving even deeper
into the physiology of sex.


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And now, with orgasm,


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the involuntary contraction
of the outer vaginal ring.


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Laboratory studies led to
revelations


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about what happened to
the female body during sex.


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The lubrication of the vagina
came from its walls


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and not from the cervix
as previously thought,


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the important role of the clitoris
in female orgasm was confirmed,


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the vagina could contract and expand


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to accommodate a variety of sizes
of penis,


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and sexual satisfaction didn't seem
to depend on penis size.


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By understanding
the physiology of normal sex,


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Masters and Johnson hoped to help
those with sexual problems.


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Science was starting to get to grips
with sex -


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to understand how our bodies carried
out this important function.


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But although their findings
were detailed,


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those sexual pioneers
lacked the technology


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to get the whole picture
of how we made love.


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In particular,


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they couldn't see what was going on
inside the human body during sex.


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Reproductive physiologist
Dr Roy Levin


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has struggled with the technical
limitations of studying sex


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for decades.


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we didn't really
have the apparatus


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to allow us to do the measurements,
and there was a long period of time


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when you could only guess
what was happening


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from the external appearances
of men and women in coitus,


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so you couldn't really tell
what was happening inside


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because you just can't see.


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Our understanding of sex
hasn't moved on much


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since Leonardo da Vinci
first started dissecting corpses


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and studying them over 500 years ago.


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The Queen holds this drawing
by Leonardo


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in her very own private collection.


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The machine Dr Levin's come to see
is this fMRI scanner.


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It's basically a camera
which uses magnetic fields


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to penetrate human flesh.


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Today, in the interests of science,


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Michael DeGroot
and his girlfriend Liz Leahy


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are going to attempt to have sex
in its cramped confines.


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Well, this is the machine.


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As you can see inside
it's got, like, two doughnuts,


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those are the very large magnets,


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and in between is the space that
you'll lie down in and have coitus.


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So, it's been specially adapted,


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that means just a single board
has been put down


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and you'll lay in between
the two magnets,


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and hopefully that will capture
the images of what's going on


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during sexual intercourse. OK.


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00:13:06,400 --> 00:13:10,240
Dr Levin is well aware of the
problems that need to be overcome


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if this experiment
is to be successful.


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00:13:13,040 --> 00:13:16,200
It's not the easiest thing
in the world to maintain an erection


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00:13:16,200 --> 00:13:21,240
and have intercourse
in terms of this particular set-up.


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00:13:21,240 --> 00:13:24,040
They're brave people
that go into these machines.


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I'm interested to see how
we're going to manoeuvre ourselves


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00:13:26,840 --> 00:13:29,520
in there, because it looks like
a pretty constricted space.


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00:13:29,520 --> 00:13:33,280
I know they want us
in one certain position,


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00:13:33,280 --> 00:13:36,560
so I hope that we're able
to situate ourselves


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00:13:36,560 --> 00:13:38,840
so that they get the images
that they want.


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00:13:38,840 --> 00:13:40,520
That's my main concern.


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00:13:47,920 --> 00:13:50,760
The scanner takes a picture
every three seconds


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and produces images of the body
from top to bottom.


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00:13:55,520 --> 00:13:58,520
This is the first time
that such images have been seen


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00:13:58,520 --> 00:13:59,920
on British television.


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00:14:01,720 --> 00:14:03,600
You can sort of see the penis here,


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00:14:03,600 --> 00:14:05,920
that's outside the body
from about here,


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00:14:05,920 --> 00:14:08,320
and this is the root of the penis
inside the body,


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00:14:08,320 --> 00:14:11,200
and this is inside the female's
body, that's her pubic symphysis,


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00:14:11,200 --> 00:14:14,040
the bone, and here would be
the pubic hair just around here.


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00:14:14,040 --> 00:14:15,520
That's, of course, her bottom


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00:14:15,520 --> 00:14:17,520
and this is the vagina
that the penis is in,


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00:14:17,520 --> 00:14:19,080
and at the top here is the glans.


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00:14:19,080 --> 00:14:21,600
And the thing that is obvious
in this cross-section


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is the unusual shape of the penis
during intercourse.


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00:14:24,680 --> 00:14:26,040
Well, it's like a boomerang,


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00:14:26,040 --> 00:14:28,560
that's what we've found out
by these machines, actually.


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00:14:28,560 --> 00:14:31,160
That in fact the penis
does look like a boomerang.


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00:14:31,160 --> 00:14:34,520
It isn't straight, like they
drew it in the early times.


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00:14:34,520 --> 00:14:38,640
In fact it is bent,
as you can see quite clearly.


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It's actually incredible,


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00:14:39,960 --> 00:14:43,760
because as far as
when you're having an erection,


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00:14:43,760 --> 00:14:48,000
you think it's as hard and solid
as...rock or wood or something,


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00:14:48,000 --> 00:14:50,360
but when you look at those pictures
it's unbelievable,


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00:14:50,360 --> 00:14:51,760
you have the 90-degree angle,


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00:14:51,760 --> 00:14:54,240
and you can't even imagine
that it would bend that way.


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00:14:54,240 --> 00:14:56,840
It's really fascinating
to see what the body does.


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00:14:58,120 --> 00:15:00,760
Nobody knows why the penis
has to go through


242
00:15:00,760 --> 00:15:03,440
such extraordinary contortions.


243
00:15:03,440 --> 00:15:05,880
One theory is that
it's a relic from our past,


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00:15:05,880 --> 00:15:10,520
when sex was more commonly done
on all fours, and not face to face.


245
00:15:22,520 --> 00:15:25,320
Understanding the mechanics
of sex and desire


246
00:15:25,320 --> 00:15:29,280
gave scientists the knowledge they
needed to move to the next stage,


247
00:15:29,280 --> 00:15:32,880
of trying to fix
our many sexual problems.


248
00:15:32,880 --> 00:15:37,240
Male impotence seemed to be one of
the most obvious issues to tackle.


249
00:15:37,240 --> 00:15:41,640
But the first idea of how to fix
erectile dysfunction


250
00:15:41,640 --> 00:15:45,080
wouldn't come
from a scientific laboratory.


251
00:15:54,120 --> 00:15:58,360
Instead, the breakthrough came
from a man named Geddings Osbon.


252
00:15:58,360 --> 00:16:01,120
He ran a tyre retreading company,


253
00:16:01,120 --> 00:16:05,400
but he became one of history's
most unexpected medical innovators


254
00:16:05,400 --> 00:16:09,520
when he came up with a very
practical mechanical solution


255
00:16:09,520 --> 00:16:11,480
for his own impotence.


256
00:16:12,640 --> 00:16:16,200
The only thing he knew about
was maybe taking a small pump.


257
00:16:16,200 --> 00:16:20,280
At this time he got
a regular bicycle pump.


258
00:16:22,520 --> 00:16:28,600
This tube is tubing that was used
on the windshield wipers of cars.


259
00:16:31,480 --> 00:16:36,120
This metal valve is the kind of
metal valve you find on truck tyres.


260
00:16:38,720 --> 00:16:40,760
He reversed the cylinder in here,


261
00:16:40,760 --> 00:16:42,400
to make it to where...


262
00:16:42,400 --> 00:16:46,000
when he pulled up,
it created negative pressure.


263
00:16:46,000 --> 00:16:52,840
So he found that if he could take
this tube here and connect it,


264
00:16:52,840 --> 00:16:56,040
that he could pull the air
out of the cylinder,


265
00:16:56,040 --> 00:17:00,280
so then he would place this against
his body and he would pull up


266
00:17:00,280 --> 00:17:03,080
and it would pull blood
into the penis,


267
00:17:03,080 --> 00:17:06,120
and then in the cylinder
he would get an erection.


268
00:17:06,120 --> 00:17:10,000
Geddings Osbon's invention
achieved mechanically


269
00:17:10,000 --> 00:17:12,160
what the body normally does itself -


270
00:17:12,160 --> 00:17:15,480
drawing blood
into the spongy erectile tissue


271
00:17:15,480 --> 00:17:18,120
which runs the length of the penis.


272
00:17:18,120 --> 00:17:20,360
When an erection happens naturally,


273
00:17:20,360 --> 00:17:24,040
the rising pressure inside the penis
closes down the veins


274
00:17:24,040 --> 00:17:27,800
to stop blood leaving
and maintain the erection.


275
00:17:27,800 --> 00:17:31,120
Osbon used an elastic band.


276
00:17:31,120 --> 00:17:34,680
His system was reluctantly adopted
by the medical community


277
00:17:34,680 --> 00:17:36,800
in the 1980s.


278
00:17:36,800 --> 00:17:41,080
For years, the vacuum erection pump
was the only mainstream solution


279
00:17:41,080 --> 00:17:43,400
to a very common problem.


280
00:17:43,400 --> 00:17:46,200
But it's easy to understand
that Osbon's invention


281
00:17:46,200 --> 00:17:49,680
didn't suit every man
suffering from impotence.


282
00:17:49,680 --> 00:17:52,480
What was needed
was something more convenient,


283
00:17:52,480 --> 00:17:55,320
that didn't ruin the moment.


284
00:17:58,600 --> 00:18:01,920
The solution came in the form
of a chemical compound


285
00:18:01,920 --> 00:18:04,520
developed in the late '90s.


286
00:18:08,200 --> 00:18:11,840
Scientists at Pfizer were
looking for a new drug for angina,


287
00:18:11,840 --> 00:18:15,160
something that would relax
the blood vessels around the heart.


288
00:18:17,560 --> 00:18:20,720
After screening
hundreds of thousands of compounds,


289
00:18:20,720 --> 00:18:25,120
they ended up with UK-92,480.


290
00:18:25,120 --> 00:18:27,880
But its trials in humans
were a letdown.


291
00:18:27,880 --> 00:18:30,160
It was about to be consigned
back to the stores


292
00:18:30,160 --> 00:18:35,000
when the triallists came back
reporting an unusual side effect -


293
00:18:35,000 --> 00:18:36,760
lots of erections.


294
00:18:38,880 --> 00:18:41,400
Add the drug, and the relaxations
get larger.


295
00:18:41,400 --> 00:18:44,160
But it's... The trace's upside down.


296
00:18:44,160 --> 00:18:47,800
By making a crude mock-up
of the human sexual apparatus,


297
00:18:47,800 --> 00:18:52,280
senior scientist Chris Wayman
found an ingenious way


298
00:18:52,280 --> 00:18:54,360
to test this anecdotal evidence.


299
00:18:57,800 --> 00:18:59,960
These are actually
penile blood vessels


300
00:18:59,960 --> 00:19:02,040
that we have in a tissue bath.


301
00:19:03,880 --> 00:19:07,560
Think of this as the brain, this is
the brain and the spinal cord.


302
00:19:07,560 --> 00:19:10,600
When you become aroused,
your brain switches on.


303
00:19:10,600 --> 00:19:11,760
We can mimic this


304
00:19:11,760 --> 00:19:17,240
by switching on the equivalent of the
central nervous system in the brain.


305
00:19:17,240 --> 00:19:22,400
It sends electricity down to the
tissue baths and across the tissues.


306
00:19:22,400 --> 00:19:24,280
And when we pass an electric current


307
00:19:24,280 --> 00:19:27,840
across these small pieces
of penile tissue, they relax,


308
00:19:27,840 --> 00:19:31,440
and ultimately that's what happens
during penile erection.


309
00:19:33,560 --> 00:19:37,720
Relaxed penile blood vessels
mean more blood flow to the penis,


310
00:19:37,720 --> 00:19:40,240
and so an erection.


311
00:19:40,240 --> 00:19:44,760
What Chris did was take penile
blood vessels from impotent men,


312
00:19:44,760 --> 00:19:47,720
vessels that didn't respond
when he flipped the brain-switch,


313
00:19:47,720 --> 00:19:51,200
and then added UK-92,480
to the tissue bath.


314
00:19:52,880 --> 00:19:55,040
What was most amazing
about this study


315
00:19:55,040 --> 00:19:58,320
was that we saw a restoration of
erectile response.


316
00:19:59,920 --> 00:20:02,880
It's very rare
in any tissue preparation


317
00:20:02,880 --> 00:20:06,880
to convert dysfunctional
to normal function.


318
00:20:06,880 --> 00:20:10,720
So now we were onto something that
can only be described as special.


319
00:20:13,640 --> 00:20:19,120
UK-92,480 was renamed Viagra.


320
00:20:19,120 --> 00:20:21,320
And within weeks of going on sale,


321
00:20:21,320 --> 00:20:25,680
tens of thousands of prescriptions
were being written every day.


322
00:20:28,960 --> 00:20:30,960
You would never have been able
to predict


323
00:20:30,960 --> 00:20:33,800
that this was going to
have beneficial effects


324
00:20:33,800 --> 00:20:36,880
on millions and millions of men
throughout the world.


325
00:20:36,880 --> 00:20:41,200
A little bit of science having
an effect of self-esteem, anxiety,


326
00:20:41,200 --> 00:20:45,800
depression levels and ultimately
creating enhanced relationships.


327
00:21:12,280 --> 00:21:16,040
Today, Viagra is one of
the most widely prescribed drugs


328
00:21:16,040 --> 00:21:20,640
in the world, with about six tablets
being dispensed every second.


329
00:21:20,640 --> 00:21:22,840
By fumbling in the dark,


330
00:21:22,840 --> 00:21:27,160
science had fixed a problem
that had plagued men for centuries.


331
00:21:29,400 --> 00:21:31,920
But there are bigger
and deadlier problems


332
00:21:31,920 --> 00:21:33,280
when it comes to sex,


333
00:21:33,280 --> 00:21:36,600
and some of them would prove
much more resistant


334
00:21:36,600 --> 00:21:38,240
to scientific solutions.


335
00:21:44,800 --> 00:21:49,440
Sex brings bodies into intimate
physical contact with each other.


336
00:21:49,440 --> 00:21:53,760
But it also allows sexually
transmitted diseases to travel


337
00:21:53,760 --> 00:21:55,680
from one person to another.


338
00:21:57,640 --> 00:22:02,080
But by the 1970s many of these
diseases were under control -


339
00:22:02,080 --> 00:22:04,040
in the developed world at least.


340
00:22:06,440 --> 00:22:12,640
Then, in the early 1980s, along came
a terrifying new sexual infection.


341
00:22:12,640 --> 00:22:16,160
Horizon broadcast
one of the first documentaries


342
00:22:16,160 --> 00:22:18,240
about this terrible new disease.


343
00:22:19,880 --> 00:22:22,200
The first troubling signs
were noticed


344
00:22:22,200 --> 00:22:24,920
in the homosexual communities
of America,


345
00:22:24,920 --> 00:22:28,120
in particular in
New York's Greenwich Village.


346
00:22:29,920 --> 00:22:32,760
Gay men were contracting
bizarre infections


347
00:22:32,760 --> 00:22:35,800
that seldom infected healthy people.


348
00:22:35,800 --> 00:22:40,440
Toxoplasmosis,
Pneumocystis carinii pneumonia,


349
00:22:40,440 --> 00:22:44,000
Cryptosporidiosis,
and types of tuberculosis


350
00:22:44,000 --> 00:22:49,440
that normally only infected birds
were killing men in their prime.


351
00:22:49,440 --> 00:22:52,880
Then the disease was noticed
in intravenous drug users,


352
00:22:52,880 --> 00:22:57,720
many of who were in prison by the
time they started having symptoms.


353
00:22:57,720 --> 00:23:00,360
Prisoner Castranova's speech
is affected.


354
00:23:00,360 --> 00:23:02,080
He may have Toxoplasmosis


355
00:23:02,080 --> 00:23:03,760
as well as the pneumonia.


356
00:23:03,760 --> 00:23:05,760
This is one of his better days.


357
00:23:05,760 --> 00:23:07,440
What's rough now is,


358
00:23:07,440 --> 00:23:10,880
I don't know
if I'll ever see my kids again.


359
00:23:10,880 --> 00:23:13,480
Scientists were horrified
when they looked at blood


360
00:23:13,480 --> 00:23:15,400
taken from these patients.


361
00:23:15,400 --> 00:23:18,200
The numbers of a particular
white blood cell,


362
00:23:18,200 --> 00:23:22,640
known as a T helper cell,
were at rock bottom.


363
00:23:22,640 --> 00:23:25,880
Without this vital cornerstone
of the immune system,


364
00:23:25,880 --> 00:23:29,000
infections which would normally be
easily fended off


365
00:23:29,000 --> 00:23:31,320
could become lethal.


366
00:23:31,320 --> 00:23:34,240
Finally, behind all these
odd infections,


367
00:23:34,240 --> 00:23:37,400
scientists discovered
a puppet master.


368
00:23:37,400 --> 00:23:39,720
Something that was weakening
the immune system,


369
00:23:39,720 --> 00:23:43,240
allowing other, usually mild,
infections to wreak havoc.


370
00:23:44,480 --> 00:23:46,040
They tracked down the cause


371
00:23:46,040 --> 00:23:51,360
of what had become known as acquired
immunodeficiency syndrome - AIDS.


372
00:23:52,840 --> 00:23:56,320
It was a virus - HIV.


373
00:23:59,000 --> 00:24:01,280
Like a walking time bomb.


374
00:24:02,760 --> 00:24:04,280
You know?


375
00:24:04,280 --> 00:24:05,920
That's what they said.


376
00:24:06,920 --> 00:24:10,040
"You're like a walking time bomb."


377
00:24:10,040 --> 00:24:12,080
He died soon after.


378
00:24:12,080 --> 00:24:15,000
And Mrs Castranova also died.


379
00:24:15,000 --> 00:24:18,240
She was incubating AIDS
while her husband was in prison.


380
00:24:20,840 --> 00:24:24,040
Since HIV was first identified,


381
00:24:24,040 --> 00:24:27,600
over 60 million people have become
infected worldwide.


382
00:24:28,960 --> 00:24:34,120
Of those who contracted the virus,
AIDS has killed 30 million people.


383
00:24:35,480 --> 00:24:39,080
It's one of the worst pandemics
the world has ever known.


384
00:24:40,880 --> 00:24:45,320
In the intervening years,
science has scrambled to find drugs


385
00:24:45,320 --> 00:24:48,680
that could cure the disease,
with only limited success.


386
00:24:54,680 --> 00:24:56,280
COCKEREL CROWS


387
00:24:58,840 --> 00:25:01,200
But then something surprising
was noticed


388
00:25:01,200 --> 00:25:03,560
in a valley in Central Africa.


389
00:25:03,560 --> 00:25:06,160
Something which would suggest
an effective way


390
00:25:06,160 --> 00:25:08,120
of combating the disease.


391
00:25:15,240 --> 00:25:19,040
On one side of the valley people
are dying of AIDS in their hundreds,


392
00:25:19,040 --> 00:25:22,680
while their neighbours, with the same
apparent behaviour and risk,


393
00:25:22,680 --> 00:25:25,520
are far less affected by the disease.


394
00:25:25,520 --> 00:25:29,800
MAN SPEAKS IN OWN LANGUAGE


395
00:25:29,800 --> 00:25:33,400
In this school, if the epidemic
continues to spread,


396
00:25:33,400 --> 00:25:37,200
60% of these children
will die from AIDS.


397
00:25:43,880 --> 00:25:45,640
But the extraordinary thing is


398
00:25:45,640 --> 00:25:47,880
that if they were children
just a mile away


399
00:25:47,880 --> 00:25:49,600
on the other side of this valley,


400
00:25:49,600 --> 00:25:53,280
their chances of dying
would be three times less.


401
00:25:59,000 --> 00:26:01,600
Scientists realised
the only difference


402
00:26:01,600 --> 00:26:05,000
between the AIDS-free side
of the valley and the other


403
00:26:05,000 --> 00:26:07,160
was that the boys
on the healthy side


404
00:26:07,160 --> 00:26:11,120
had been circumcised,
according to local custom.


405
00:26:11,120 --> 00:26:15,600
Removing the foreskin seemed
to have an almost miraculous effect


406
00:26:15,600 --> 00:26:18,600
in preventing the men
from getting infected.


407
00:26:21,000 --> 00:26:22,400
Intrigued by the idea,


408
00:26:22,400 --> 00:26:25,640
anthropologist Priscilla Reining
compiled data


409
00:26:25,640 --> 00:26:29,520
on hundreds of circumcised
and uncircumcised tribes.


410
00:26:30,920 --> 00:26:34,840
When this data was matched up
with a map of HIV prevalence,


411
00:26:34,840 --> 00:26:37,160
the correlation was startling.


412
00:26:37,160 --> 00:26:39,680
This was the map which we published,


413
00:26:39,680 --> 00:26:46,000
and the black are depicting
ethnic groups


414
00:26:46,000 --> 00:26:51,960
which do not practice circumcision
as a norm, and the grey


415
00:26:51,960 --> 00:26:55,680
are groups
which do practice circumcision.


416
00:26:55,680 --> 00:26:59,840
So this is a corridor which runs
from the southern Sudan


417
00:26:59,840 --> 00:27:01,360
down into South Africa.


418
00:27:02,720 --> 00:27:07,480
Here is an overlay of HIV.


419
00:27:07,480 --> 00:27:11,200
And you can see that
there's a high degree of conformity


420
00:27:11,200 --> 00:27:17,840
between the red, which is
relatively high HIV rates.


421
00:27:17,840 --> 00:27:23,560
There is red
down the same band, and...


422
00:27:26,320 --> 00:27:28,960
..interestingly,
over here as well.


423
00:27:31,600 --> 00:27:33,440
The statistical...


424
00:27:33,440 --> 00:27:39,320
statistical relationship was .90,
which is very good.


425
00:27:39,320 --> 00:27:42,760
And so, you know, wow,
it really is there.


426
00:27:47,120 --> 00:27:48,920
But why should circumcision


427
00:27:48,920 --> 00:27:52,120
so drastically cut the risk
of HIV infection?


428
00:27:53,160 --> 00:27:56,760
The answer lay in particular cells
of the immune system


429
00:27:56,760 --> 00:27:58,480
present in the foreskin.


430
00:27:58,480 --> 00:28:01,200
Cells which HIV was targeting.


431
00:28:09,920 --> 00:28:13,200
The green cells
are Langerhans cells.


432
00:28:13,200 --> 00:28:16,760
They're in the front line of
the body's battle against infection.


433
00:28:16,760 --> 00:28:20,320
They capture infectious agents
like viruses


434
00:28:20,320 --> 00:28:22,920
and show them to other cells
of the immune system,


435
00:28:22,920 --> 00:28:25,240
which can actively fight
the infection.


436
00:28:28,920 --> 00:28:33,280
But HIV uses the Langerhans cells
as a gateway to the body.


437
00:28:37,280 --> 00:28:39,400
It's a Trojan horse, basically.


438
00:28:39,400 --> 00:28:45,600
The Langerhans cell is in fact
allowing the virus to enter the body,


439
00:28:45,600 --> 00:28:49,720
and carry to the very system,
namely the lymph glands,


440
00:28:49,720 --> 00:28:52,520
where those viruses
can start proliferating.


441
00:29:04,200 --> 00:29:09,800
Circumcision reduces the risk of
being infected by HIV by over 60%,


442
00:29:09,800 --> 00:29:13,120
and is now recommended
by the World Health Organisation


443
00:29:13,120 --> 00:29:15,680
as an important part
of disease prevention.


444
00:29:18,800 --> 00:29:22,200
It's hoped that HIV/ AIDS
will be vanquished one day,


445
00:29:22,200 --> 00:29:25,000
but for the moment the disease
is being held at bay


446
00:29:25,000 --> 00:29:29,600
by a mixture of anti-retroviral
drugs and sex education.


447
00:29:37,000 --> 00:29:39,920
As well as tackling diseases
that spread amongst us


448
00:29:39,920 --> 00:29:41,640
through sexual contact,


449
00:29:41,640 --> 00:29:46,280
scientists have also tried to help
with problems of gender identity.


450
00:29:47,600 --> 00:29:50,840
Biologically speaking,
it should be straightforward.


451
00:29:50,840 --> 00:29:55,680
After all, the chromosomes we get
from our parents determine our sex.


452
00:29:55,680 --> 00:30:01,160
Two X chromosomes for a girl,
an X and a Y chromosome for a boy.


453
00:30:04,800 --> 00:30:08,360
Beyond that simple equation, though,
scientists are still studying


454
00:30:08,360 --> 00:30:13,520
how exactly our genes
turn us into either men or women.


455
00:30:23,160 --> 00:30:26,640
Of course, there's much more
to being female or male


456
00:30:26,640 --> 00:30:30,280
than just which body parts
you do or don't have.


457
00:30:30,280 --> 00:30:34,920
What makes us feel
and act like men or women?


458
00:30:34,920 --> 00:30:38,800
There has been a long debate
over how much our gender identity


459
00:30:38,800 --> 00:30:42,040
is controlled by nature or nurture.


460
00:30:42,040 --> 00:30:44,400
And for the latter half
of the 20th century,


461
00:30:44,400 --> 00:30:49,160
the argument focused
on the tragic story of one boy.


462
00:30:54,720 --> 00:31:00,960
On 27th April 1966, Janet Reimer
took her baby twin boys


463
00:31:00,960 --> 00:31:04,680
Bruce and Brian to her local
hospital in Winnipeg, Canada,


464
00:31:04,680 --> 00:31:06,840
for a routine circumcision.


465
00:31:08,320 --> 00:31:10,520
But instead of using a knife,


466
00:31:10,520 --> 00:31:14,880
doctors chose to use an electric
cauterisation technique.


467
00:31:14,880 --> 00:31:18,760
Bruce went first,
but the equipment malfunctioned,


468
00:31:18,760 --> 00:31:21,920
and Bruce's penis
was burned beyond repair.


469
00:31:24,520 --> 00:31:26,520
Janet was devastated.


470
00:31:27,920 --> 00:31:30,120
Daily, I was crying.


471
00:31:30,120 --> 00:31:32,400
Every time I changed his diaper
I'd cry.


472
00:31:33,560 --> 00:31:35,000
I was in shock...


473
00:31:36,960 --> 00:31:38,080
..for a while.


474
00:31:39,920 --> 00:31:43,080
I guess about a year I was in shock.


475
00:31:44,680 --> 00:31:49,160
Janet had no idea what to do
after the botched operation.


476
00:31:49,160 --> 00:31:52,440
Until, one night,
she saw a glimmer of hope


477
00:31:52,440 --> 00:31:54,240
when she was watching a talk show.


478
00:31:55,680 --> 00:32:01,160
One of the guests was a radical
psychologist called Dr John Money.


479
00:32:01,160 --> 00:32:04,040
Dr John Money, a psychologist
at John Hopkins,


480
00:32:04,040 --> 00:32:07,560
is one of the leading advocates
of sex-change operations.


481
00:32:07,560 --> 00:32:11,480
Dr Money is in the bear pit
tonight with Alvin Davis.


482
00:32:11,480 --> 00:32:16,360
Dr Money, it's still a pretty
drastic procedure, isn't it?


483
00:32:16,360 --> 00:32:22,080
Well, it's a drastic procedure
by your standards and mine,


484
00:32:22,080 --> 00:32:24,840
but for the people
who are living in desperation,


485
00:32:24,840 --> 00:32:27,640
perhaps the best way
to understand it


486
00:32:27,640 --> 00:32:31,200
is that it seems no more drastic
to them than circumcision.


487
00:32:34,680 --> 00:32:37,760
Hoping that something
could be done for her son,


488
00:32:37,760 --> 00:32:39,840
Janet wrote to Dr Money.


489
00:32:39,840 --> 00:32:42,240
He called back as soon as
he got her letter.


490
00:32:44,760 --> 00:32:48,560
Dr Money needed Bruce's
unique case to prove a theory


491
00:32:48,560 --> 00:32:50,440
he had been working on.


492
00:32:50,440 --> 00:32:54,080
His theory was that gender
wasn't just down to genes -


493
00:32:54,080 --> 00:32:56,000
that it was much more malleable.


494
00:32:57,680 --> 00:33:01,840
He believed that you could take a
child who was genetically one sex


495
00:33:01,840 --> 00:33:04,520
and raise it successfully
as the other -


496
00:33:04,520 --> 00:33:07,320
provided you started in infancy.


497
00:33:07,320 --> 00:33:10,480
His theory was known
as Gender Neutrality.


498
00:33:14,440 --> 00:33:17,320
Faced with an almost impossible
decision,


499
00:33:17,320 --> 00:33:22,200
on Dr Money's advice, Janet had
her two-year-old son castrated.


500
00:33:22,200 --> 00:33:27,880
From then on he was dressed
and raised as a girl, called Brenda.


501
00:33:27,880 --> 00:33:31,400
When Dr Money announced his work
with the Reimers to the world,


502
00:33:31,400 --> 00:33:33,440
he was hailed as a genius.


503
00:33:36,040 --> 00:33:40,640
His theory on the malleability
of gender became hugely influential


504
00:33:40,640 --> 00:33:44,720
amongst doctors and psychologists
around the world.


505
00:33:44,720 --> 00:33:46,600
But there was a problem.


506
00:33:46,600 --> 00:33:48,960
Unbeknownst to
the scientific community,


507
00:33:48,960 --> 00:33:51,360
the experiment had gone wrong.


508
00:34:08,280 --> 00:34:10,000
I didn't like dressing like a girl,


509
00:34:10,000 --> 00:34:11,640
I didn't like behaving like a girl,


510
00:34:11,640 --> 00:34:13,520
I didn't like acting like a girl.


511
00:34:15,600 --> 00:34:19,040
Brenda Reimer was now living
as a man called David.


512
00:34:22,960 --> 00:34:27,840
After the operation, Brenda had been
taught to dress and act like a girl.


513
00:34:27,840 --> 00:34:30,120
But she felt like a boy.


514
00:34:31,480 --> 00:34:33,720
Well, I wore dresses on occasion.


515
00:34:35,600 --> 00:34:38,080
And I never played
with girl's stuff,


516
00:34:38,080 --> 00:34:41,000
I usually got stuck with dolls
or something like that,


517
00:34:41,000 --> 00:34:44,200
for my birthday or Christmas.


518
00:34:44,200 --> 00:34:46,840
They sat in a corner
collecting dust.


519
00:34:46,840 --> 00:34:48,560
I played with my brother's things.


520
00:34:53,840 --> 00:34:57,200
During the early years, I thought
we had made the right choice -


521
00:34:57,200 --> 00:35:01,960
that it would work out. Dr Money
kept saying it would work out.


522
00:35:01,960 --> 00:35:05,760
And I thought, well, he should know.


523
00:35:09,080 --> 00:35:13,840
But when Brenda was 14, her parents,
realising the confusion and misery


524
00:35:13,840 --> 00:35:19,120
caused by her changed identity,
told her and her brother the truth.


525
00:35:19,120 --> 00:35:23,400
You don't wake up one morning
and say, "Oh, I'm a boy today."


526
00:35:23,400 --> 00:35:25,240
You know? You know!


527
00:35:25,240 --> 00:35:29,280
It's in you! You know, it's in
your genetics, it's in your brain.


528
00:35:29,280 --> 00:35:31,480
Nobody has to tell you who you are.


529
00:35:32,880 --> 00:35:38,120
Dr Money's experiment to
raise a boy as a girl had failed,


530
00:35:38,120 --> 00:35:41,920
and the story of the Reimer brothers
ended with tragedy.


531
00:35:44,480 --> 00:35:47,200
Unable to deal with
what had happened to David,


532
00:35:47,200 --> 00:35:51,800
his brother Brian became depressed
and died from a drug overdose.


533
00:35:53,000 --> 00:35:55,160
Traumatised by his brother's death,


534
00:35:55,160 --> 00:35:58,480
and with a catalogue of personal
disasters in his adult life,


535
00:35:58,480 --> 00:36:02,120
in 2004, David shot himself.


536
00:36:03,520 --> 00:36:05,600
It didn't work because that's life.


537
00:36:05,600 --> 00:36:08,720
Because you're human,
and you're not stupid,


538
00:36:08,720 --> 00:36:12,480
and eventually...
you'll end up being who you are.


539
00:36:26,240 --> 00:36:29,960
The tragic story of David Reimer
seems to show that


540
00:36:29,960 --> 00:36:34,360
the roots of our gender identity
lie in genetics and not in nurture.


541
00:36:34,360 --> 00:36:38,120
And indeed evidence that Dr Money's
theory might have been flawed


542
00:36:38,120 --> 00:36:41,080
was already emerging
in the late 1960s,


543
00:36:41,080 --> 00:36:45,320
just as he was announcing
his supposedly successful theory.


544
00:36:45,320 --> 00:36:50,480
That evidence came from the brain
of a rat in Los Angeles.


545
00:36:55,000 --> 00:36:57,560
A team from the University
of California


546
00:36:57,560 --> 00:37:00,800
were comparing male
and female rat brains


547
00:37:00,800 --> 00:37:02,680
in minute detail.


548
00:37:04,160 --> 00:37:06,840
They were hoping to find
a physical difference


549
00:37:06,840 --> 00:37:11,040
that would explain differences
in male and female behaviour.


550
00:37:13,160 --> 00:37:16,040
Slice by slice,
millimetre by millimetre,


551
00:37:16,040 --> 00:37:18,720
they mapped the tiny organs.


552
00:37:22,600 --> 00:37:25,480
And one day, they found something.


553
00:37:28,520 --> 00:37:30,960
Comparing tissue
from the hypothalamus,


554
00:37:30,960 --> 00:37:32,880
right in the centre of the brain,


555
00:37:32,880 --> 00:37:36,280
they noticed a structural
difference between the sexes.


556
00:37:39,160 --> 00:37:43,720
A discrete part of the hypothalamus
was twice as big


557
00:37:43,720 --> 00:37:46,600
in the male rat's brain,
on the left,


558
00:37:46,600 --> 00:37:49,480
as in the female's, on the right.


559
00:37:54,480 --> 00:37:59,080
Here's that part, isolated
from the brain of a male rat.


560
00:37:59,080 --> 00:38:03,840
They called it the sexually
dimorphic nucleus, or SDN.


561
00:38:03,840 --> 00:38:06,800
And here it is in
the female rat's brain.


562
00:38:11,160 --> 00:38:13,960
Here was a clear
anatomical difference


563
00:38:13,960 --> 00:38:17,040
between the brains of
male and female rats.


564
00:38:18,440 --> 00:38:23,160
These differences are created by
sex hormones before the rat is born.


565
00:38:23,160 --> 00:38:25,240
While a male rat is in the womb,


566
00:38:25,240 --> 00:38:28,360
testosterone is already
shaping its brain.


567
00:38:30,920 --> 00:38:34,600
The SDN is also larger
in the human male brain,


568
00:38:34,600 --> 00:38:36,800
compared with the female.


569
00:38:38,200 --> 00:38:41,680
And the SDN is involved
in sexual behaviour.


570
00:38:43,800 --> 00:38:46,920
The discovery of the SDN was
important because it showed


571
00:38:46,920 --> 00:38:50,080
that there were real differences
in the brains of men and women.


572
00:38:51,840 --> 00:38:55,680
And other real-life cases
showed that gender identity


573
00:38:55,680 --> 00:38:58,880
was already permanently
programmed at birth.


574
00:39:01,520 --> 00:39:05,400
Dr Money's experiment
was ultimately flawed, because of


575
00:39:05,400 --> 00:39:09,680
the way that hormones affected
the fledgling brain of the baby.


576
00:39:12,560 --> 00:39:16,680
But while gender identity is
fixed at birth for most people,


577
00:39:16,680 --> 00:39:20,000
for others,
it's much less cut-and-dried.


578
00:39:22,520 --> 00:39:26,600
If called upon,
science sometimes has a solution.


579
00:39:29,280 --> 00:39:34,480
Max Toft, a software engineer, is
physically and genetically a woman.


580
00:39:34,480 --> 00:39:36,520
But she wants to be a man.


581
00:39:38,320 --> 00:39:41,600
I remembered having this
distinct moment where I thought


582
00:39:41,600 --> 00:39:44,360
that God had made a mistake and
that I should have been a boy -


583
00:39:44,360 --> 00:39:47,680
which was interesting, because
I grew up in an atheist household!


584
00:39:48,720 --> 00:39:50,800
To make her body more male,


585
00:39:50,800 --> 00:39:54,080
Max is going to undergo
a course of testosterone.


586
00:39:54,080 --> 00:39:56,720
Dr Ruben Gur,
one of the leading scientists


587
00:39:56,720 --> 00:39:58,840
on how hormones affect the brain,


588
00:39:58,840 --> 00:40:02,640
is going to put Max though a series
of physical and psychological tests


589
00:40:02,640 --> 00:40:05,200
before and after her treatment.


590
00:40:08,000 --> 00:40:09,760
Go.


591
00:40:12,880 --> 00:40:16,720
UPBEAT MUSIC PLAYS


592
00:40:25,920 --> 00:40:27,560
Stop.


593
00:40:27,560 --> 00:40:32,320
Max shows a fairly
typical female, erm,


594
00:40:32,320 --> 00:40:35,040
profile, cognitively.


595
00:40:35,040 --> 00:40:41,520
Erm, and, er, I'd be curious to see
whether there is a change in that.


596
00:40:43,320 --> 00:40:46,560
After six months of
testosterone therapy,


597
00:40:46,560 --> 00:40:49,760
the most obvious changes
are to Max's body -


598
00:40:49,760 --> 00:40:53,280
his voice is deeper,
and he's got more body hair.


599
00:41:01,640 --> 00:41:04,720
But it's the psychological
and practical tests Max underwent


600
00:41:04,720 --> 00:41:08,720
before and after hormone treatment
which have been the most startling.


601
00:41:12,760 --> 00:41:15,440
What we are seeing, really, is, er,


602
00:41:15,440 --> 00:41:19,000
is a female brain turning into
a male brain. It was quite, er,


603
00:41:19,000 --> 00:41:22,520
quite amazing to see it
on a single individual.


604
00:41:23,680 --> 00:41:26,800
This is a scan of Max's brain
when he was a woman.


605
00:41:26,800 --> 00:41:30,040
The red areas show
the parts of the brain he used


606
00:41:30,040 --> 00:41:32,400
when trying to read emotions.


607
00:41:32,400 --> 00:41:37,440
And this is a scan of Max's brain
doing the same task but as a man.


608
00:41:37,440 --> 00:41:41,320
The more red in the scan picture,
the harder the brain is working.


609
00:41:41,320 --> 00:41:44,280
And as you can see, it seems
that he found it much easier


610
00:41:44,280 --> 00:41:47,240
to read emotions when he
was a woman than he does now.


611
00:41:48,640 --> 00:41:51,840
In his case, the second time, he had


612
00:41:51,840 --> 00:41:55,440
more difficulties with the task,
he had to put in more effort


613
00:41:55,440 --> 00:41:59,240
in order to perform that
particular...that particular task.


614
00:41:59,240 --> 00:42:03,160
So, he's... His brain
responds more like a male brain


615
00:42:03,160 --> 00:42:06,880
to the task of trying
to distinguish the emotions.


616
00:42:12,920 --> 00:42:16,040
But how did Max do
in the practical tests?


617
00:42:20,640 --> 00:42:24,760
All the changes are in the direction
that we expected,


618
00:42:24,760 --> 00:42:27,320
in terms of becoming more masculine.


619
00:42:27,320 --> 00:42:30,600
Interesting. Er, so,
remember the finger-tapping?


620
00:42:30,600 --> 00:42:35,200
Uh-huh. You managed to squeeze in
another three taps


621
00:42:35,200 --> 00:42:37,560
per minute. Whoo-hoo!


622
00:42:37,560 --> 00:42:41,320
His spatial awareness
has also dramatically improved.


623
00:42:41,320 --> 00:42:44,000
Last time, you did 75 correct.


624
00:42:44,000 --> 00:42:46,640
This time, you did 118 correct.


625
00:42:46,640 --> 00:42:49,880
Right. That's pretty much
the end of the good news... Right.


626
00:42:49,880 --> 00:42:53,320
..because, er, with becoming a male,


627
00:42:53,320 --> 00:42:55,560
erm, you also lost a little bit.


628
00:42:56,920 --> 00:42:59,360
Max's visual memory
has deteriorated,


629
00:42:59,360 --> 00:43:01,720
and he's not as good with words.


630
00:43:01,720 --> 00:43:04,440
I was actually surprised.
I didn't...


631
00:43:04,440 --> 00:43:08,200
I was thinking maybe one or two...


632
00:43:08,200 --> 00:43:11,560
tests would change, and, er...


633
00:43:11,560 --> 00:43:15,880
Erm, this is after all
a fairly brief period of time.


634
00:43:15,880 --> 00:43:18,920
You would expect changes
on those tests


635
00:43:18,920 --> 00:43:21,880
to take place over a longer period.


636
00:43:24,360 --> 00:43:25,800
Max is still sceptical


637
00:43:25,800 --> 00:43:29,800
about the extent to which
testosterone has changed his brain.


638
00:43:29,800 --> 00:43:33,600
But he acknowledges
it has affected how he feels.


639
00:43:33,600 --> 00:43:38,320
My body is changing, and it has
been surprising to go through that.


640
00:43:38,320 --> 00:43:42,040
It's been kind of exciting, and
there were changes that I wasn't...


641
00:43:42,040 --> 00:43:44,600
that I didn't expect to go through.
There was a period of time


642
00:43:44,600 --> 00:43:46,960
where I had a really hard time
crying,


643
00:43:46,960 --> 00:43:49,200
and it felt biological to me.


644
00:43:49,200 --> 00:43:52,840
There was something biochemical
preventing me from doing it.


645
00:43:52,840 --> 00:43:55,360
Like, it really felt
like a big block,


646
00:43:55,360 --> 00:43:58,080
and that was kind of
a scary moment for me.


647
00:44:01,840 --> 00:44:05,480
For most people, the biggest
impact that science has had on


648
00:44:05,480 --> 00:44:09,520
our sex lives has been in giving us
greater control over reproduction.


649
00:44:12,400 --> 00:44:15,280
Thanks to medical advances
over recent decades,


650
00:44:15,280 --> 00:44:19,120
today, more healthy babies
are born than ever before.


651
00:44:24,000 --> 00:44:26,400
And the invention of
the contraceptive pill


652
00:44:26,400 --> 00:44:29,920
gave women the power
to decide when they have them.


653
00:44:36,040 --> 00:44:39,680
As pills go, THE Pill
is a particularly tiny one,


654
00:44:39,680 --> 00:44:43,000
and yet its effect
on the sex lives of women


655
00:44:43,000 --> 00:44:45,160
has been monumental.


656
00:44:45,160 --> 00:44:49,240
But behind this little piece
of sexual liberation


657
00:44:49,240 --> 00:44:51,880
is the story of
an intrepid scientist


658
00:44:51,880 --> 00:44:55,640
who went to the ends of the earth,
and then disappeared.


659
00:45:01,240 --> 00:45:04,120
In order to make
a contraceptive pill for women,


660
00:45:04,120 --> 00:45:08,960
scientists needed a source
of the sex hormone progesterone.


661
00:45:08,960 --> 00:45:11,640
But in the early part
of the last century,


662
00:45:11,640 --> 00:45:14,000
producing these hormones
in a laboratory


663
00:45:14,000 --> 00:45:17,200
was difficult,
and phenomenally expensive.


664
00:45:19,880 --> 00:45:23,480
But Professor Russell Marker,
of Pennsylvania State University,


665
00:45:23,480 --> 00:45:25,280
had an idea.


666
00:45:25,280 --> 00:45:27,440
He knew that some animal hormones


667
00:45:27,440 --> 00:45:30,160
were very similar
to chemicals in plants,


668
00:45:30,160 --> 00:45:33,560
and he identified
a raw botanic ingredient


669
00:45:33,560 --> 00:45:37,640
that theoretically could be used
to produce progesterone.


670
00:45:42,920 --> 00:45:44,600
Using the roots of a yucca plant


671
00:45:44,600 --> 00:45:47,560
he found in the
south-western United States,


672
00:45:47,560 --> 00:45:49,840
he proved his chemical principle.


673
00:45:49,840 --> 00:45:53,360
However, this plant didn't naturally
produce enough of the raw material


674
00:45:53,360 --> 00:45:55,960
to ever be economically viable.


675
00:45:57,160 --> 00:46:01,680
Then, in November 1941, Marker
found what he was looking for.


676
00:46:01,680 --> 00:46:06,680
In an old botany textbook,
he saw a rare type of wild yam


677
00:46:06,680 --> 00:46:12,160
with an enormous root system that
was said to weigh almost 100 kilos.


678
00:46:12,160 --> 00:46:14,600
But there was a problem -


679
00:46:14,600 --> 00:46:19,240
the yam only grew in an isolated
region of the Mexican jungle.


680
00:46:24,680 --> 00:46:27,360
The intrepid Marker
travelled there alone


681
00:46:27,360 --> 00:46:30,320
and smuggled two huge roots
of this rare plant


682
00:46:30,320 --> 00:46:33,040
back to the United States.


683
00:46:36,560 --> 00:46:41,080
Once home, he successfully
synthesised 2kg of progesterone -


684
00:46:41,080 --> 00:46:44,120
far more than anyone
had ever seen before.


685
00:46:45,400 --> 00:46:47,520
Marker wanted to go into business,


686
00:46:47,520 --> 00:46:50,800
but he was shunned by
the major pharmaceutical companies,


687
00:46:50,800 --> 00:46:53,520
so he founded his own,
called Syntex,


688
00:46:53,520 --> 00:46:56,280
and began to produce
more progesterone.


689
00:46:59,280 --> 00:47:02,840
But in 1949, with
business about to boom,


690
00:47:02,840 --> 00:47:05,840
Marker mysteriously vanished.


691
00:47:07,880 --> 00:47:10,000
His work would lay the foundations


692
00:47:10,000 --> 00:47:14,000
for the production of the modern
contraceptive pill in the 1960s.


693
00:47:14,000 --> 00:47:17,600
But Marker himself was
still nowhere to be found.


694
00:47:17,600 --> 00:47:22,680
It was rumoured that he'd died
in a mental institution in Mexico.


695
00:47:25,960 --> 00:47:31,120
But in 1977, Horizon tracked down
the elusive professor.


696
00:47:31,120 --> 00:47:35,600
He was living just a few miles away
from Penn State University,


697
00:47:35,600 --> 00:47:38,800
where he first made
his remarkable discovery.


698
00:47:38,800 --> 00:47:42,280
In this interview from the time,
it's not difficult to see


699
00:47:42,280 --> 00:47:46,120
why Marker had become
so disillusioned with big business.


700
00:47:46,120 --> 00:47:47,240
At the end of the year,


701
00:47:47,240 --> 00:47:49,840
when I thought the profits
should be distributed...


702
00:47:49,840 --> 00:47:52,360
I knew that there
were very nice profits,


703
00:47:52,360 --> 00:47:54,880
including the profit
that was obtained


704
00:47:54,880 --> 00:47:58,160
from the first 2kg of progesterone
that I had made.


705
00:47:58,160 --> 00:48:02,040
And I had made
25 or 30kg during the year


706
00:48:02,040 --> 00:48:08,400
of progesterone - it was
selling for over 25 a gram


707
00:48:08,400 --> 00:48:10,200
at that time.


708
00:48:10,200 --> 00:48:13,800
I went to the senior partner
in the firm


709
00:48:13,800 --> 00:48:17,240
and asked him about the profits,
and he said there were no profits.


710
00:48:17,240 --> 00:48:20,080
And he eventually told me that, er,


711
00:48:20,080 --> 00:48:22,040
he had taken the profits as salary,


712
00:48:22,040 --> 00:48:24,400
and there was nothing
I could do about it.


713
00:48:24,400 --> 00:48:26,800
So I walked out of Syntex.


714
00:48:39,520 --> 00:48:44,080
The Pill gave women the power
to prevent unwanted pregnancies.


715
00:48:44,080 --> 00:48:46,560
But for couples who want children,


716
00:48:46,560 --> 00:48:49,720
becoming pregnant
can sometimes be difficult.


717
00:48:49,720 --> 00:48:52,840
Many problems can interfere
with conception,


718
00:48:52,840 --> 00:48:55,120
causing anguish for parents.


719
00:48:57,720 --> 00:49:01,040
It was once thought that being able
to control this natural process


720
00:49:01,040 --> 00:49:02,920
would be impossible.


721
00:49:02,920 --> 00:49:07,800
Then, in 1978, a baby was born
using a radical new technique


722
00:49:07,800 --> 00:49:11,360
that has revolutionised
the treatment of infertility.


723
00:49:14,920 --> 00:49:17,760
Researchers removed eggs
from the mother


724
00:49:17,760 --> 00:49:21,400
and combined them with sperm
from the father in a Petri dish.


725
00:49:22,680 --> 00:49:24,280
The embryologists could then check


726
00:49:24,280 --> 00:49:26,960
to see if the embryo's development
was proceeding normally


727
00:49:26,960 --> 00:49:30,440
before re-implanting
only the most healthy embryos


728
00:49:30,440 --> 00:49:33,760
back into the mother,
for nature to take its course.


729
00:49:36,400 --> 00:49:40,520
The technical name for the procedure
is in vitro fertilisation,


730
00:49:40,520 --> 00:49:42,320
or IVF.


731
00:49:42,320 --> 00:49:46,640
The media coined the phrase
"test-tube babies".


732
00:49:47,720 --> 00:49:50,440
At the time, it was
highly controversial.


733
00:49:52,600 --> 00:49:56,920
Since those early days, hundreds
of thousands of healthy babies


734
00:49:56,920 --> 00:49:59,200
have started their lives
in this way,


735
00:49:59,200 --> 00:50:01,160
and the stigma has gone.


736
00:50:01,160 --> 00:50:04,600
It's one of science's
greatest success stories.


737
00:50:08,240 --> 00:50:12,920
But the moral dilemmas thrown up
by test-tube babies didn't vanish.


738
00:50:12,920 --> 00:50:14,320
People began to worry that


739
00:50:14,320 --> 00:50:16,920
the technique gave scientists
the opportunity


740
00:50:16,920 --> 00:50:21,880
to do far more than simply helping
infertile couples have babies.


741
00:50:23,080 --> 00:50:25,960
IVF meant that it one day
might be possible


742
00:50:25,960 --> 00:50:28,720
to tamper with the DNA
of an embryo in the lab


743
00:50:28,720 --> 00:50:31,240
and create a bespoke baby.


744
00:50:35,960 --> 00:50:38,400
30 years ago, Horizon made a drama


745
00:50:38,400 --> 00:50:41,600
where families were no longer
prepared to leave the appearance


746
00:50:41,600 --> 00:50:44,480
and character of their children
to chance.


747
00:50:46,120 --> 00:50:49,040
You've got two girls - are you
certain you don't want a boy?


748
00:50:49,040 --> 00:50:52,320
Yes, quite sure - we really do
want another girl. Yes, definitely.


749
00:50:52,320 --> 00:50:56,160
Right. Well, you've had a chance
to view the data at home?


750
00:50:56,160 --> 00:50:59,600
Yes. We've narrowed it down
to zygote 3 and 6 -


751
00:50:59,600 --> 00:51:02,800
we're not really sure
which one to choose.


752
00:51:04,160 --> 00:51:06,360
What sort of characteristics
were you thinking of?


753
00:51:06,360 --> 00:51:08,040
We definitely don't want to tamper


754
00:51:08,040 --> 00:51:10,880
with the physical side of things
in any way. No, except that


755
00:51:10,880 --> 00:51:13,000
we would like her to have
my father's red hair.


756
00:51:13,000 --> 00:51:16,080
Ah. Ah, well, that's easy.


757
00:51:16,080 --> 00:51:19,880
We can make her homozygous
on the three hair colour genes.


758
00:51:21,040 --> 00:51:24,000
What about her character
and emotions? Ah, well, yes,


759
00:51:24,000 --> 00:51:27,480
there are a few things we'd like
to have modified if possible.


760
00:51:27,480 --> 00:51:29,880
We'd like to reduce shyness,


761
00:51:29,880 --> 00:51:32,080
and susceptibility to depression...


762
00:51:33,200 --> 00:51:37,600
..without necessarily damaging...
any artistic potential.


763
00:51:37,600 --> 00:51:41,080
Also, we'd like her to be musical,
and if possible,


764
00:51:41,080 --> 00:51:43,400
also we want her to be ambitious.


765
00:51:45,080 --> 00:51:48,680
A world where we could pre-order
genetic traits for our children


766
00:51:48,680 --> 00:51:51,960
might seem fanciful,
but in some ways,


767
00:51:51,960 --> 00:51:54,280
it's already here.


768
00:51:54,280 --> 00:51:58,120
IVF has given embryologists
the opportunity to screen embryos


769
00:51:58,120 --> 00:52:00,080
for genetic problems.


770
00:52:00,080 --> 00:52:03,840
These techniques have helped women
like Philippa Handyside,


771
00:52:03,840 --> 00:52:06,560
for whom having children
was impossible.


772
00:52:09,560 --> 00:52:12,200
Just kept miscarrying all the time.


773
00:52:12,200 --> 00:52:16,720
And it just actually got quite normal
- that was actually how awful it was.


774
00:52:16,720 --> 00:52:19,840
It was very hard,
and it sounds really harsh,


775
00:52:19,840 --> 00:52:22,720
but you just kind of get...
It just becomes part of life.


776
00:52:22,720 --> 00:52:26,000
I used to get pregnant, lose it,
pregnant, lose it, and that was it.


777
00:52:35,320 --> 00:52:39,080
Philippa Handyside wasn't trying
to create the perfect child -


778
00:52:39,080 --> 00:52:41,640
she just wanted to have a baby.


779
00:52:43,040 --> 00:52:45,160
But she wasn't having any luck.


780
00:52:46,640 --> 00:52:51,160
So she underwent testing to see why
she was having so many miscarriages.


781
00:52:55,240 --> 00:52:58,040
The cause of her miscarriages
was genetic -


782
00:52:58,040 --> 00:53:00,440
the result of a chromosome disorder.


783
00:53:01,600 --> 00:53:04,640
It meant most of her embryos didn't
have the right combination of genes


784
00:53:04,640 --> 00:53:07,200
they needed to grow healthily.


785
00:53:08,880 --> 00:53:12,080
There was nothing Philippa's
local hospital could do for her -


786
00:53:12,080 --> 00:53:14,600
it seemed she might never
have children.


787
00:53:17,360 --> 00:53:20,440
But then, Philippa
heard about a new technique.


788
00:53:21,760 --> 00:53:25,320
It's a technique some people think
could lead to designer babies.


789
00:53:36,400 --> 00:53:40,440
The technique is called
preimplantation genetic diagnosis,


790
00:53:40,440 --> 00:53:42,160
or PGD.


791
00:53:43,600 --> 00:53:48,280
Using PGD, scientists can
screen embryos outside the womb,


792
00:53:48,280 --> 00:53:50,800
long before they develop
into babies.


793
00:53:52,320 --> 00:53:56,000
Then, they can select just those
embryos that carry healthy genes


794
00:53:56,000 --> 00:53:59,920
to ensure the baby is free
from genetic abnormalities.


795
00:53:59,920 --> 00:54:03,280
PGD is one of those ideas
that's so clever


796
00:54:03,280 --> 00:54:06,520
that it seems impossible to do.
I mean, how could you possibly


797
00:54:06,520 --> 00:54:09,800
take a very early embryo and
take out a cell and diagnose it?


798
00:54:09,800 --> 00:54:12,600
Well, in the end,
it transpired that the embryo


799
00:54:12,600 --> 00:54:14,200
is such a tough little beast


800
00:54:14,200 --> 00:54:16,960
that it actually allows you to do
fairly outrageous things to it,


801
00:54:16,960 --> 00:54:18,760
without noticing.


802
00:54:20,920 --> 00:54:22,960
To do PGD, the doctors first


803
00:54:22,960 --> 00:54:26,320
had to extract eggs
from Philippa's ovaries.


804
00:54:27,880 --> 00:54:32,240
These eggs were then fertilised
by her husband's sperm in a lab.


805
00:54:34,800 --> 00:54:38,600
The fertilised eggs were allowed
to develop into a cluster of cells.


806
00:54:53,000 --> 00:54:56,320
You phone every day and you're
told how they're getting on.


807
00:54:56,320 --> 00:54:58,960
It's like having children
in nursery - you're told every day


808
00:54:58,960 --> 00:55:01,040
how they're progressing through.


809
00:55:02,440 --> 00:55:05,440
Then, 48 hours after fertilisation,


810
00:55:05,440 --> 00:55:09,920
acid was used to etch a hole
in the membrane of each embryo,


811
00:55:09,920 --> 00:55:12,880
and a single cell sucked out.


812
00:55:19,280 --> 00:55:21,640
And on day three
after their collection,


813
00:55:21,640 --> 00:55:24,560
we've taken a single cell
from each embryo,


814
00:55:24,560 --> 00:55:27,320
and we've sent those cells to
our genetics team across the road,


815
00:55:27,320 --> 00:55:30,520
so they can make
the molecular diagnosis.


816
00:55:33,120 --> 00:55:35,280
The theory is that if the analysis


817
00:55:35,280 --> 00:55:38,480
shows the genes are normal
in the single cell,


818
00:55:38,480 --> 00:55:42,640
then the embryo is came from
will also be genetically normal.


819
00:55:42,640 --> 00:55:45,920
That's OK - two blue...


820
00:55:45,920 --> 00:55:47,400
Two green,


821
00:55:47,400 --> 00:55:49,480
two red, so that's fine.


822
00:55:51,320 --> 00:55:54,640
Eventually, they found cells
from two of Philippa's embryos


823
00:55:54,640 --> 00:55:56,440
that had healthy genes.


824
00:55:57,440 --> 00:55:59,320
They called us through and said,


825
00:55:59,320 --> 00:56:02,160
"Yep, we've got a couple."
The geneticist said,


826
00:56:02,160 --> 00:56:05,600
"There's one that...
it's not divided so well,


827
00:56:05,600 --> 00:56:08,760
"but the other one, brilliant,
absolutely brilliant.


828
00:56:08,760 --> 00:56:13,680
"So, we're going to implant,
if you're happy, two back in."


829
00:56:13,680 --> 00:56:17,920
So, it was a case of,
get ready, and get kind of...


830
00:56:17,920 --> 00:56:22,360
into the room, and ready to
have the implantation...done.


831
00:56:25,440 --> 00:56:27,760
PGD allows mothers like Philippa


832
00:56:27,760 --> 00:56:31,680
to have children they would
otherwise have been denied.


833
00:56:33,080 --> 00:56:35,160
But there are those who still worry


834
00:56:35,160 --> 00:56:38,320
that this is the thin end
of the wedge,


835
00:56:38,320 --> 00:56:41,800
and that in the future, people
would be able to select embryos


836
00:56:41,800 --> 00:56:45,400
on the basis of much more
controversial genetic traits.


837
00:56:47,680 --> 00:56:51,000
The forefront of research
into sex and fertility


838
00:56:51,000 --> 00:56:54,760
continues to present us
with much trickier ethical problems


839
00:56:54,760 --> 00:56:57,600
then we've ever had to grapple with
in the past.


840
00:56:59,040 --> 00:57:02,040
But at the same time,
the science of sex


841
00:57:02,040 --> 00:57:04,920
has helped us learn about ourselves,


842
00:57:04,920 --> 00:57:08,880
to combat sexual problems
and to restore fertility.


843
00:57:15,880 --> 00:57:20,840
Sex is still the most intimate
and personal aspect of our lives.


844
00:57:20,840 --> 00:57:23,680
But since science
got into bed with us,


845
00:57:23,680 --> 00:57:27,760
we've had a much better chance
of decoding this tricky subject,


846
00:57:27,760 --> 00:57:30,720
and of understanding ourselves.


847
00:57:30,720 --> 00:57:37,360
We know so much more about sex now
than we did just a few decades ago,


848
00:57:37,360 --> 00:57:41,000
and I think our lives
are better for it.


849
00:57:51,680 --> 00:57:54,520
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