Caster Semenya is the fastest 800m runner in the world this year. As she prepares to take her first steps towards winning her first Olympic gold medal in Rio de Janeiro tonight, the 25-year-old South African returns to the familiar and unwanted spotlight.

Semenya, who will compete in the 800-meter race in Rio, suffers from hyperandrogenism, a condition that causes a person to produce excess testosterone. Because of this, Semenya has spent her career – and even her status as a woman – under public scrutiny.

The runner burst onto the scene in 2009 when she ran 1: 55.45 to win gold in the 800 meters at the IAAF World Championships in Berlin. Semenya won by more than two seconds, an eternity for the two-round event.

Shortly thereafter, the Australian newspaper The daily telegraph revealed that the IAAF had subjected her to a gender test. According to the leaked results published in the story, Semenya had triple the amount of testosterone a “normal” woman would have. The IAAF cleared Semenya to compete in July 2010.

Semenya continued her victory in Berlin with a silver medal in the 800 meters at the 2011 IAAF World Championships in Daegu. The following year, she won silver in that event at the 2012 London Olympics. Both of these performances came after the IAAF adopted rules requiring female athletes with hyperandrogenism to demonstrate that their testosterone levels fall below the male range in order to compete with females.

Testosterone levels are measured in nanomoles per liter (nmol / L). According to IAAF regulations, “normal” testosterone levels for male athletes are above 10.5 nmol / L, while the normal range for women is between 0.1 nmol / L and 2.8. nmol / L.

“It is not entirely clear how the IAAF established a ‘normal’ range of testosterone for their regulations, especially since there is very little research on testosterone in women outside of the populations. clinics, “wrote Sari van Anders, associate professor of psychology, Women’s Studies, Neuroscience and Reproductive Sciences at the University of Michigan, in an email exchange with Pastry. “From what I can tell, there have been a lot of unscientific subjective decisions about who to include and exclude when deciding on ‘standards’. Interestingly, all the quotes about where this decision came from came from review articles, not empirical data articles, which means that someone’s opinion was quoted somewhere, which was quoted. somewhere, etc. So even the scientific basis for standards is based on someone’s subjective decision. rather than objective empirical data.

According to van Anders, the regulations put in place by the IAAF were unfair to female athletes with naturally higher testosterone levels.

“I am shocked by the regulations adopted without any scientific or convincing basis; it may sound like ‘common sense’ that high testosterone equals superior masculinity and athletic performance, but there are reasons we use science and not common sense to determine certain types of truth ” , wrote van Anders. “There is literally no scientific evidence linking athletes’ athletic performance to their testosterone levels, despite decades of relevant data. And, even the most basic behavioral neuroendocrinology textbook helps Hormone 101 students understand that sex and gender have a number of influences, of which hormones may or may not be a part.

“One more reason, among many, why the regulations were unfair: Although the IAAF says its hyperandrogenicity regulations are not a form of sexual testing, it sounds like legal jargon that is all. simply false and illogical. The regulations only apply to women (i.e. only women are prohibited from competing if they have androgen levels higher than gender-specific) and clearly high androgens are used as a de facto test of femininity; new genital parade by hormone dosing, if you will, ”van Anders added in his email.

IAAF regulations, which required Semenya and athletes like her to lower their testosterone levels in order to compete, took a toll on her career. At the 2015 IAAF World Championships in Beijing, the South African failed to advance to the 800-meter final after running 2: 03.18 in the semi-final.

IAAF rules were tested in 2015 when Dutee Chand, an Indian athlete who also suffers from hyperandrogenism, sued the IAAF for her right to compete as a woman. The Court of Arbitration for Sport ruled in favor of Chand, writing the following in his conclusion:

The IAAF has not provided sufficient scientific evidence on the quantitative relationship between increased testosterone levels and improved athletic performance in hyperandrogenic athletes. In the absence of such evidence, the Panel is unable to conclude that hyperandrogenic female athletes can enjoy such a significant performance advantage that it is necessary to exclude them from competing in the female category.

Katrina Karkazis is a senior researcher at the Center for Biomedical Ethics at Stanford University who was an expert witness in the Chand case (Sari van Anders was also an expert witness in the case). Karkazis said the IAAF policy was wrong because, among other reasons, it mixed up two separate issues.

“What the policies do very quickly is go from a problem of categories (where some people fall, why shouldn’t we have some women in the category of women) to questions of unfair advantages,” Karkazis said. “So it’s really two separate issues that got mixed up. “

The Chand case gave rise to the IAAF suspends its rules for hyperandrogenic female athletes. As a result, Semenya was allowed to resume competition with her natural testosterone levels. Now she’s back on top.

In April, Semenya won three national titles in about four hours at the South African Championships. His winning times in the 400m and 800m were both Olympic qualifiers, and his time in the 1,500m was just off the mark.

She set a new personal best in the 800 meters on July 15, clocking 1: 55.33 to win the Meeting Herculis in Monaco and set the Diamond League record. This race took place after she won the Relay titles 800 meters, 1,500 meters and 4 × 400 meters at the African athletics championships. Semenya has set three of the world’s five fastest times in the 800 meters this year. She is dominant.

Semenya is expected to win gold in Rio. Karkazis fears the political debate over hyperandrogenism overshadows Semenya’s achievements on the trail.

“I want her, as well as she does, to be able to celebrate her accomplishments without scrutiny,” Karkazis said. “She deserves it because she’s worked as hard as anyone else, with incredible dedication, from the last Olympics to where she is now. If people want to continue debating politics, and they will because it’s up to CAS, they don’t need to be part of that debate. Anyone who understands the evidence knows that a sample proves nothing. It is therefore not a debate about her and she should be excluded from it.

Some of the women Semenya will compete against in the Olympics have made their views known on what they see as an unfair race.

“I think it calls into question and threatens the integrity of women’s sport to have intersex athletes competing against genetic women,” said Shannon Rowbury after the first round of the 1,500 meters at this year’s US Olympic Trials. “I think Caster is a wonderful person, I have nothing against her. But I think we already have a precedent set in men’s and women’s sports and I think we have to honor that.”

Brenda Martinez, who will represent the United States in Rio as a 1,500-meter runner, said she was open to competition from Semenya, but that she would like to see the IAAF regulations for restored testosterone levels.

“Personally, I think she should compete. I love Caster, she was so nice to me, ”Martinez said after the first round of the 800m at the US Olympic Trials. “I don’t think anyone should be turned down. It’s just not fair, it’s not the subject of our sports. Yes, she is different but it is not her fault. I love her, I respect her, I want to run her.

Karkazis said she believes Semenya’s competitors might think this situation is unfair because of the way the IAAF handled it.

“I think if it weren’t for the 2009 investigation and drama, it’s possible that people wouldn’t view it as unfair,” Karkazis said. “In other words, they take what they think they understand about her body and what they think they understand about testosterone and athletics, and look at her and assume that her current performance is all due to that.”

Karkazis also added that because Semenya does not fit the supposed idea of ​​femininity for many people, it is easier for people to doubt her.

“But I think something more sinister is going on here as well,” Karkazis said. “Caster Semenya does not present herself in a stereotypical feminine fashion to many watching. And I think they go very quickly from his presentation on the genre to a lot of hypotheses about its physiology.

Semenya is not without its supporters, however. Eleni Schirmer, doctoral student at the University of Wisconson-Madison, published an open letter to the South African to ESPNW July 1.

“I will support you because you are creating a legacy for all humans with bodies. You make us look at the categories we think we belong to, the categories we think are structuring the world, ”writes Schirmer in the letter to Semenya.

Karkazis and van Anders have also made it clear that they believe this debate should be about a larger issue and that the focus on Semenya alone is unfair.

“One of the tragedies of all of this is that what should be a debate about a policy has been reduced to a debate about an individual,” Karkazis said.

For van Anders, the media’s focus on Semenya is unethical.

“The media present a public face to this debate, and I would like to see the IAAF presented as the public face,” van Anders wrote in an email. “It seems unethical for publications to continue to question and distinguish the sex or gender of an athlete for the sake of profit or sensation.”

Michael Sol Warren is a Boston-based freelance writer. Follow him on Twitter @MSolDub.