NARRATOR: Intersex.
Even if you've heard the word, you may not know what it is.
And that's not surprising because intersex
doesn't mean just one thing.
It refers to a variety of different conditions
in which a child is born with anatomy that doesn't completely
conform to what's traditionally understood
to be male or female.
By one estimate, one in 1,500 babies
is born intersex, which would make it about as common
as being born with red hair.
If that number is true, then we
certainly all know somebody who is intersex,
even if we don't know it.
NARRATOR: And while intersex isn't exactly
a household word, last summer it got global attention
at the Rio Olympics.
Caster Semenya, the lightning fast runner from South Africa.
She took gold in the 800 meter but she almost didn't
make it to the starting blocks.
She was nearly banned from competing at all
after allegations that she is intersex, reportedly born
with a condition that causes her body to produce extremely
high levels of testosterone, something critics,
and the women who have to compete against her,
say is an unfair advantage.
High testosterone is the most important factor that separates
male and female athletes.
If you allow intersex women to compete against other women
with their naturally-produced high testosterone,
it creates a very un-level playing field.
NARRATOR: Not everyone agrees that testosterone gives elite
athletes the gold medal edge.
Some sports scientists argue it's
no more of an unfair advantage than good nutrition
or good genes.
So the task that policymakers have been given is to basically
prove that testosterone is jet fuel
that's propelling them and giving
them male-typical advantage.
And so it's not borne out by their times,
but it's also not borne out by the science.
NARRATOR: But in 2011, the governing body
in track and field instituted a controversial new rule banning
any female runner with testosterone levels
higher than 10 nanomoles per liter, considered by experts
to be in the male range.
It's not saying you are a man or a woman.
It's saying you can compete.
It's a matter of eligibility to participate
in certain competitions.
So it places a ceiling or a threshold limit on women's
natural testosterone.
And if you exceed that, even though you've
always competed in the women's category,
you're no longer eligible.
NARRATOR: The ruling meant Caster Semenya was sidelined
unless she was willing to artificially
lower her testosterone levels with drugs,
which she presumably did.
And her performance suffered.
But the pressure on her, demanding public answers
to intimate questions, never let up.
Yeah they can make their own decisions.
But don't forget, what I can do I can just help other athletes
like me, you know?
NARRATOR: And some asked, was Semenya
singled out not just because of her speed on the track?
I think what happened was really
based on her appearance that crosses
some sort of invisible threshold of femininity.
She didn't fit what people would expect from a female athlete.
NARRATOR: Caster seemed destined to miss the Rio games.
But in 2015, the ban was lifted when a runner from India, Dutee
Chand, also barred because of high testosterone levels,
sued the international track and field governing authority
and won after sports officials failed to produce
scientific data to back up their theory
that testosterone gives female athletes
an insurmountable advantage.
The scientific evidence wasn't there,
which is underlying the rationale
for the entire policy.
Higher testosterone gives you male typical advantage.
And that wasn't borne out.
NARRATOR: With the ban lifted, Semenya
went on to win gold in Rio.
But in at least one way, Semenya's victory
was bittersweet, exposing the raw emotions
and deep sense of injustice some of her fellow runners felt.
There's a really sad, I think, and heartbreaking
photograph that sticks with me.
So after Caster Semenya had won her race
she went over to greet competitors who had not
medaled, reaching out to try to greet them
and they remain in the embrace.
What it points to, really, is a very sad,
heartbreaking ending about who's really
harmed by these policies.
NARRATOR: And Semenya may have another hurdle
to clear before she crosses the finish line.
The track and field governing authority
has until July of 2017 to provide
scientific evidence about the role
of testosterone in athletes.
If they meet the deadline, the ban could be reinstated
and Caster Semenya could be stripped of her medals
and sidelined forever.