Caster Semenya told HBO that she offered to show her vagina to athletics officials when she was 18 to prove she was a woman.

The two-time Olympic champion, now 31, burst onto the scene in 2009 when she won the women’s 800m world title by a stunning margin, hours after the sport’s world governing body announced that she would undergo gender verification tests.

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Caster Semenya on @RealSportsHBO this week. When she took anti-testosterone drugs to be eligible: “I didn’t know if I was having a heart attack. It’s like stabbing myself with a knife every day, but I had no choice.” pic.twitter.com/QzGMieyCqD

—Nick Zaccardi (@nzaccardi) May 23, 2022

“They thought I had a dick, probably,” Semenya said in an interview with HBO’s Real Sports, which airs Tuesday night. “I told them, ‘It’s okay. I’m a woman, I don’t care. If you want to see that I’m a woman, I’ll show you my vagina. OK?'”

Gender tests on Semenya reportedly showed the runner had no uterus or ovaries, but had internal testicles, the male sex organs that produce testosterone, and her hormone levels were three times higher than those usually expected in a woman. Semenya has a condition known as hyperandrogenism, which is characterized by higher than usual levels of testosterone, a hormone that increases muscle mass and strength and the body’s ability to use oxygen.

She took medication after the first ruling in 2011 by World Athletics – then the International Association of Athletics Federations – that all female athletes with hyperandrogenism should medically lower their testosterone levels.

“It made me sick, made me gain weight, had panic attacks, I don’t know if I was going to have a heart attack,” Semenya told HBO. “It’s like stabbing yourself with a knife every day. But I had no choice. I’m 18, I want to run, I want to go to the Olympics, it’s the only option for me.

World Athletics lawyer Jonathan Taylor, who also appeared on the HBO show, disagreed with medical panels, including the World Medical Association, which condemned the sport’s governing body for forcing women with differences in sexual development to take medication to compete.

“You say medically it’s not healthy for me, so my question is, ‘Why are the world’s leading experts saying this is what we would prescribe?’ said Taylor.

Semenya fired back: “Jonathan must cut out his tongue and throw it away. If he wants to understand how this thing tortured me, he has to go take these drugs. He will understand.

In 2020, Semenya lost her appeal in Swiss federal court to overturn a 2019 Court of Arbitration for Sport ruling that female athletes with high natural levels of testosterone must take medication to lower it.

She had approached the court after CAS, the sport’s highest court, ruled that World Athletics regulations were needed for athletes with developmental gender differences in races ranging from 400m to one mile to ensure fair competition.