Editors Note: This story is part of As Equals, CNN’s ongoing series on gender inequality. Read more from As Equals here and read our FAQs for information about how the series is funded and more.

As an ambitious, determined teenager, Annet Negesa urged her body to run faster, and her body, always loyal, obliged her.

Even before the middle-distance runner had a coach, Negesa was qualifying for -- and winning -- major regional competitions. At 19, she would travel to Daegu in South Korea for the 2011 World Championships. After securing a top-three spot in the 800 meter and 1500 meter categories, in four international competitions, the Ugandan athlete qualified to represent her country at the 2012 London Olympics.

The following year, the young woman from Iganga, a small village in eastern Uganda, was named ‘Athlete of the Year’ by the Uganda Athletics Federation and seemed set for a life in the athletics spotlight.

That did happen -- but not in the way she had hoped. Much has been written all over the world about Negesa. Not only because of her victories on the track, but also because of what happened to her off it.

In August 2011, while at the World Championships, Negesa submitted to blood tests. According to the International Association of Athletics Federations (IAAF, now known as World Athletics) this was a requirement for all athletes competing that year.

But Negesa says she never received her test results, and without them, life continued as normal: With intense training for the London Games.

It was while in Europe, just weeks before the competition, that Negesa would get a call from her manager, informing her that she could no longer compete at the Olympics.

She says he explained that the blood samples revealed levels of the hormone, testosterone, in her blood that IAAF considered too high and that at the recommendation of the athletics governing body, she would need to get further tests.

Negesa’s bright future quickly darkened from that point. She headed to a specialist hospital in the south of France, the name of which was provided by the IAAF. There, she underwent a medical assessment that involved a further blood test and an MRI scan.

Again, Negesa says she didn’t understand what was happening, nor was she given any paperwork. “No one gave me advice ... like: ‘If you do this, you’ll get this later.’ No one explained to me what the consequences are.”

World Athletics disputes this, saying in an email that “Ms. Negesa and her team were provided with the results of the tests undertaken.” The organization also adds that it subsequently advised Negesa by email “that it was important that a medical doctor in Uganda follows up with her, and explains to her what the different therapeutic options are.”

In November 2012, after being taken to the Women’s Hospital International and Fertility Centre in Kampala, Uganda, the then 20-year-old woke up from surgery to learn her internal testes had been removed.

“I woke up finding myself having cuts under my belly and really, I was asking myself, ‘What happened to me? What they did to me?’”

Negesa says she had understood that she was being treated for hyperandrogenism -- the naturally high levels of testosterone her body produced -- but the surgery was not what she’d consented to. She says: “They gave me a suggestion of going for simple surgery or using an injection [to remove] the excessive testosterone in the body. My suggestion was using the injection.”

A medical report, seen by CNN, states that the doctors in Uganda “restrained from starting her on estrogen therapy,” claiming that they were “awaiting further discussions” with an IAAF doctor.

Estrogen was essential for Negesa’s recovery. Retired endocrinologist Peter Sonksen has not treated Negesa but noted the importance of estrogen in treating patients like her, saying: “Once the testes are removed, as in this case, the blood testosterone and estrogen levels fall to zero and the athlete is even more hormone deficient than a post-menopausal woman.” Sonksen adds: “It is essential therefore to give estrogen 'replacement' therapy. In [its] absence, [the athlete] will suffer multiple issues affecting most body systems.”

World Athletics told CNN it "had no involvement in Ms. Negesa’s treatment" and that CNN would "have to ask [the doctor in Kampala] to explain the reference in this letter."

In pain, and without the after-care that she needed, Negesa’s body could not perform as it once did. In an account of her story published by Human Rights Watch, Negesa shared that she lost her university scholarship, and then her manager dropped her.

Also facing public scrutiny for her sex, Negesa soon fell into depression, explaining that in Uganda, it was “very hard for a person like me… an intersex person.” In 2019, she was granted asylum by the German government.

At a track in Berlin, in the shadow of the 1936 Olympic stadium, Negesa is still visibly stung by her experience. She tells CNN about feeling confused at the discovery that her body was different from what she understood it to be, and feeling powerless and completely unsupported as her life unraveled. “I was still a teenager, had no choice because I had a love of the sport ... and they knew all the consequences which would come out from them.”

Referring to the IAAF, she adds: “They violated my rights as a human being. They treated me like a guinea pig.”

The hospital declined to comment, citing confidentiality. In an email to CNN, World Athletics says: “The IAAF hyperandrogenism regulations state that the treatment must be prescribed by a physician who is independent from the IAAF, and that the IAAF is in no way involved in the process. Under no circumstances may the athlete be forced to undergo any specific treatment.”

In 2013, as Negesa struggled to come to terms with what had happened to her, in neighboring Kenya, Maximila (Max) Imali was learning that athletic success could lift her and her family out of a life of poverty.

She remembers her high school coach encouraged her to train for the 800m race, rather than the sprints, telling her: “You see that you can make your family be on another level of living.”

“I just wanted to run good so that I can feed them,” Imali says of her family: Her mother, two siblings, and two orphans she also provides care for. “I was so motivated.”

In July 2014, Imali got a chance to compete at the World Junior Championships in Oregon. “It was my first time to go to such a big race,” she recalls. “And after that, I realized that I can do good.”

She excelled in the heats but fell in the finals of the 800m event.

“After I came back home, [I] sat and discussed with the coach how I can improve and what is the best thing for me to do, so that I can do good in 800m and 1500m,” she says.

But Imali didn’t get that chance. The young woman, who was quickly gaining national and international recognition, also got caught in the crosshairs of IAAF regulations.

Once in Kenya, Imali says she received a call from an official with Athletics Kenya, telling her: "Maximila, they want you to be tested from the IAAF.”

So, Imali took a matatu minibus from Eldoret to a hospital in an upscale Nairobi neighborhood for a blood test and a physical examination.

Consistent with Negesa’s account, Imali says she was given little information about the procedures or their consequences. Referring to the hospital’s physicians, she says: “They did not tell me anything concerning my body. After we did every examination, they were just putting the results in the envelope. Then they take that envelope to Athletics Kenya."

It would be several months before Imali would learn from her manager, over a phone call, that she would not be allowed to compete in the 800m category.

She says she was told: “Max, you cannot run because you have high testosterone in your blood.” He went on to list all the races she could not compete in and shared a letter from IAAF explaining the regulations.

Weighed down by the questions about her gender identity that the assessments had thrown up, Imali went to speak to her mother. What she heard reassured her. “For me, I've been raising you like a girl from the start when you were born, and that is it. I know you are a girl,” she recalls her mother saying.

But Imali says that being rejected for how God made her, as well as the questions about her sporting, future all took a toll on her mother’s health, and in September 2016, Eunice Khaleha died.

“My mom was hospitalized because of me, because of the pressure,” Imali says, her voice filled with sorrow and regret. “She died because of me. It still affects me because I always feel that I'm the cause of her death.”

Many sporting events, from track and field to gymnastics, swimming to basketball, are divided according to a binary separation of genders. Modern medical consensus notwithstanding, as far as much of the sports world is concerned, there are only two recognized categories: Men and women.

However, Negesa and Imali both have -- or had -- levels of testosterone that their sports’ governing body officials deemed too high for some of the women’s competitions.

World Athletics now has a set of rules for athletes with what it calls differences of sex development (DSD), requiring them to lower the naturally occurring levels of testosterone in their blood to 5 nanomoles per liter of blood (5 nmol/L) through medication or surgery if they want to compete in certain races.

Non-compliance means that athletes with DSD cannot compete in events such as the 400m or 800m races put on by World Athletics.

Most high-profile among the athletes affected by the DSD regulations is South African runner and Olympic champion Caster Semenya, whose long-fought legal battle to be able to compete in the 800m event is currently before the European Court of Human Rights.

After her lawyers filed their lawsuit to the court on February 25, Semenya tweeted: “This fight is not just about me, it's about taking a stand and fighting for dignity, equality and the human rights of women in sport.”

While Semenya’s dispute with World Athletics is over a decade old, the fight to compete on equal terms goes back almost a century.

After much opposition (the founder of the modern Olympics movement, Baron Pierre de Coubertin, was against the inclusion of women in the Games), women’s participation in sport began to grow early in the 20th century. As competition in the women’s category intensified, the bodies of athletes -- and in particular, successful ones -- were scrutinized.

The attention didn’t come exclusively from the sporting bodies. Media commentators over the decades have helped peddle a narrow vision of what it means to be -- and to look like -- a woman.

Three days after the opening of the Rome Olympics in 1960, William Barry Furlong, reporting for The New York Times, wrote a piece entitled “Venus Wasn't a Shot-Putter,” in which he reflected: “More and more of the fair sex are competing in sports, raising a profound question: Do men make passes at athletic lasses?”

As “gender-normalizing” surgeries became more common in the Global North, and more athletes from the Global South have come to dominate in track and field events, it is Dutee Chand, Maximila Imali, Annet Negesa and Caster Semenya -- among others -- who have come into the media spotlight and under World Athletics’ watchful gaze.

“World Athletics wants to recognize people however they identify,” World Athletics’ legal counsel, Jonathan Taylor, tells CNN. “The problem with that is, on the sports field, we've already established that there has to be a distinction between male and female competition in order to promote fairness and equality.”

He continues: “Once you've decided that, once you've drawn a line, you have to classify people and that means deciding why the line is drawn.”

Taylor positions World Athletics as being in a bind: Needing to weigh in on an issue it would rather not have to, but must, in order to take away, as he puts it, the “enormous, insuperable advantage that's conferred by these higher testosterone levels'' in events such as the 400m, 800m, 1500m and 400m hurdles races -- all of which World Athletics classified as “restricted events” in 2019.

“If you have someone with a female gender identity, but XY testes and male levels of testosterone, you have to decide what to do. You could say: ‘You cannot compete in the female category’, which World Athletics does not want to do, because it wants to acknowledge and recognize the gender identity. So instead, they say you have to drop your testosterone down to the same levels as all the women and all the other women in the category,” he says.

Contrary to Taylor’s claim, “all women'' in the category do not have the same testosterone level.

Under World Athletics’ rules, an athlete with polycystic ovary syndrome, for example, can compete despite having high testosterone because they have XX chromosomes and no testes. Athletes with high testosterone levels whose bodies do not respond to the hormone can also compete in the restricted categories.

And so World Athletics, in so doggedly guarding the line it has drawn, has positioned itself as an arbiter of what it means to be a woman in sport. Taylor says it's done "to promote fairness and equality.” But the rules are based on scientific research that is heavily contested.

“There is good evidence to show muscle bulk increases with increasing dosage of testosterone,” Sonksen, who has previously spoken out in support of Semenya, said in an email to CNN, but adds that the relationship between blood testosterone level and performance remains “complex and controversial”.

“Measuring blood testosterone level gives some indication of the amount that is produced and testosterone does increase protein, thus muscle synthesis, but [the hormone’s] action is regulated also by other factors,” he explains.

“[World Athletics] are trying to refine further and further as the policies come under scrutiny. But the science is still very much contested,” says Katrina Karkazis, anthropologist and co-author of ‘Testosterone: An Unauthorized Biography’, a 2019 book which sets out to debunk some of the myths around the hormone.

When it comes to athletic performance, Karkazis and her co-author, Rebecca M. Jordan-Young, write about studies that have linked high natural testosterone to speed and power, studies that found no link, and yet others which show the converse to be true: High testosterone leading to worse performance.

Karkazis told CNN that the lack of conclusive evidence hasn’t stopped World Athletics from forming its policies. She cites, by way of example, a ruling by the Court of Arbitration for Sport (CAS) which states that in the 1500m and 1 mile races, the evidence of actual significant athletic advantage “could be described as sparse.” CAS recommended that “The IAAF may consider deferring the application of the DSD regulations to these events until more evidence is available.”

“Even when the evidence wasn't there, [World Athletics] decided to include it and regulate it anyway,” says Karkazis.

Not only are these regulations -- introduced and enforced without consensus from across the scientific community -- being framed as good for the games, Taylor, speaking for World Athletics, also suggests that they are good for athletes with DSD.

“We're not stopping people from competing,“ Taylor tells CNN. “We are trying to facilitate their competing” before adding: “One of the benefits of the regulations is that you identify and diagnose and treat DSD conditions as well.”

But there is increasingly vocal pushback from parts of the medical community, parents and intersex people themselves, saying that being intersex isn’t a medical “problem” to be “solved” any more so than being born male or female is one.

At the last Olympics -- the 2016 Rio Games -- Caster Semenya, Burundi’s Francine Niyonsaba, and Kenya’s Margaret Wambui took the gold, silver and bronze medals respectively in the 800m race.

This year, in Tokyo, none of these women will be competing in that category -- all three impacted, they say, by World Athletics’ rules regulating testosterone in women.

In its pursuit of fairness, affected athletes and activists alike say that World Athletics has itself been deeply unfair.

Speaking to CNN from London, academic and athletes’ rights advocate, Payoshni Mitra, says: “Rules could be necessary in sport, but those rules should also ensure safety of athletes. No rules should lead to human rights violations, and these rules are leading to human rights violations of athletes.”

For Mitra, World Athletics’ rules aren’t just sexist, they are also racist. “It clearly seems to be racist policy,” she says. “We have women's bodies from the Global South -- brown women, Black women -- in sport. Their bodies have been scrutinized more and more. It's a fact which they cannot deny.”

Taylor denies this, countering: “What we're trying to do is ensure a level playing field for all women -- of whatever color -- so that they can all aim to excel.”

The South African government didn’t see it the same way, with the then-Minister of Sports, Tokozile Xasa, weighing in to lend support to Semenya after World Athletics proposed new regulations in 2019: “Women’s bodies, their wellbeing, their ability to earn a livelihood, their very identity, their privacy and sense of safety and belonging in the world, are being questioned.”

And so, from Mitra’s perspective, it is difficult to understand World Athletics’ “adamant” focus on DSD regulations when there has already been so much suffering, so much at stake for the individual athletes, so much to lose, and so much else for the sporting world to address.

“Why they're so adamant about these regulations is really difficult to understand, given that there are so many other problems in the sport. Doping is such a huge problem in athletics. If you look at issues concerning safety of women, sexual harassment and abuse, these are such important issues in sport today … [World Athletics’ leaders] just want these people to go. They just want a purified notion of women's category without any of these athletes … What World Athletics tend to forget is athletes are human at the end of the day."

What those athletes say they want more than anything is to do what they love, without special scrutiny or restriction. They want to run as equals.

Imali, who is at home in Kenya and continues to train for the 100m and 200m sprints, is resolute: “God wanted me to be the way I am.”

As for Negesa, she has returned to the track after nearly a decade and is allowing herself to dream once again of Olympic glory: “I just pray to God that I continue doing improvements every day so that I fulfil my dream. It was snatched from me in 2012 ... I don't want to miss it again.”