In a move that has reignited one of the most divisive debates in modern athletics, World Athletics has reinstated mandatory genetic testing for female athletes at the 2025 World Championships in Tokyo. The decision, which requires competitors in the women’s category to submit to the SRY gene test—a procedure designed to detect the presence of a ‘Y’ chromosome—has stirred memories of past controversies and thrust the sport into the heart of the global conversation about fairness, inclusivity, and the definition of womanhood in elite competition.
The policy, which took effect on September 1, 2025, marks a dramatic return to a practice that was largely abandoned prior to the 2000 Sydney Olympics. At that time, sports leaders concluded the test was too intrusive and not sufficiently definitive to justify its implementation. Yet, the issue has resurfaced, with World Athletics President Seb Coe describing the new approach as necessary for the “protection and the promotion of the integrity of women’s sport.”
“This is a new thing, and we’re all going to have to face it,” remarked Faith Kipyegon, the 1,500-meter world-record holder and three-time Olympic gold medalist, echoing a sentiment of resignation among many athletes. According to World Athletics, approximately 95% of female competitors set to participate in Tokyo had completed the required test by September 12, just one day before the championships began. However, confidentiality rules have made it difficult to ascertain whether any athletes failed to comply or were subsequently ruled ineligible.
For some, the return of the SRY gene test is a necessary step to ensure a level playing field. For others, it’s a painful reminder of the hardships endured by athletes in the past. The most notable case is that of Spanish hurdler María José Martínez-Patiño, whose experiences in the 1980s helped convince sports federations to abandon genetic testing in the first place. Martínez-Patiño passed her first gender test before the 1983 World Championships and was issued a “Certificate of Femininity.” However, in 1985, she was retested at the World University Games after forgetting her certificate. The results were inconclusive, and team doctors advised her to fake an injury to explain her absence from competition.
“I sat in the stands that day watching my teammates, wondering how my body differed from theirs,” Martínez-Patiño later wrote. “I spent the rest of that week in my room, feeling a sadness that I could not share.” Further testing revealed that she had androgen insensitivity syndrome—meaning she carried a ‘Y’ chromosome, but her body did not respond to testosterone. “I lost friends, my fiancé, hope, and energy,” she reflected. “But I knew that I was a woman, and that my genetic difference gave me no unfair physical advantage.”
Her ordeal, and the broader scientific consensus that followed, led to the abandonment of gene testing for nearly two decades. Andrew Sinclair, the scientist who discovered the gene responsible for a positive SRY test, has been outspoken in his criticism of the policy’s return. “Given all the problems outlined above, the SRY gene should not be used to exclude women athletes from competition,” Sinclair wrote in a recent essay. He cited numerous potential pitfalls, including the test’s inability to detect conditions like androgen insensitivity and the risk of inaccurate results due to mishandling or inadequate laboratory facilities, particularly in less developed countries.
World Athletics has attempted to address some of these concerns by carving out an exception for athletes with “Complete Androgen Insensitivity Syndrome.” Still, critics argue that the policy is fundamentally flawed. Madeline Pape, a former elite runner and now a scholar on gender policies in sports, observed, “What’s interesting is the way the sport forgets. We’re right back to where we’re using an archaic technology for defining eligibility for the women’s category.”
Adding to the complexity, World Athletics has applied virtually identical guidelines to transgender athletes and those with differences in sex development (DSD), even though no transgender females currently compete at the elite international level. DSD athletes, who are born with a typical male XY chromosome pattern but are identified and raised as female, have found themselves at the center of the debate. The federation has allowed DSD athletes who previously complied with testosterone suppression requirements to be grandfathered into future competitions under the old rules. However, this exception would not have benefited Caster Semenya, the two-time Olympic gold medalist who has DSD and refused to suppress her testosterone.
Semenya’s long-running legal battle has been a focal point for the issue. Earlier this year, the European Court of Human Rights ruled in her favor, declaring that her rights to a fair hearing in her sex-eligibility case had been violated. “I think Caster is, in a lot of ways, the unfortunate martyr for a lot of this,” said Anna Posbergh, a Florida State researcher who studies gender in sports. “I applaud Caster for the strength she’s had to push back. But I think it was inevitable that at some point, (the test) was going to make a comeback, given the political direction the world seems to be going.”
The controversy is not confined to athletics. In the United States, a 2020 executive order signed by President Donald Trump, titled “Keeping Men Out of Women’s Sports,” has influenced policies adopted by the NCAA, the U.S. Olympic and Paralympic Committee, and institutions like the University of Pennsylvania, notably in the case of transgender swimmer Lia Thomas. Kirsty Coventry, the newly elected president of the International Olympic Committee, has campaigned on bringing clarity to the transgender athlete issue and echoed Seb Coe’s emphasis on protecting the female category. Meanwhile, the International Boxing Federation has also implemented mandatory genetic screening following similar disputes at the Paris Games.
Not all athletes agree with the direction of these policies. U.S. 1,500-meter champion Nikki Hiltz, who came out as transgender and non-binary in 2021, expressed reservations but ultimately complied with the new requirements. “Obviously, I’m gonna do it. I’m not gonna, like, protest it or anything. I just don’t like the precedent that it sets,” Hiltz said.
There has also been practical resistance. French athletes, for example, faced difficulties in meeting the September 1 deadline because their country prohibits such screening for non-medical purposes. Many were forced to undergo testing at foreign training sites en route to Tokyo, highlighting the inconsistencies and logistical hurdles that remain unresolved.
As the 2025 World Championships unfold in Tokyo, the debate over gender testing is far from settled. With about 95% of female athletes having completed the SRY gene test, the new policy is in full effect, but questions about fairness, privacy, and scientific validity continue to swirl. The world will be watching closely—not just for the performances on the track, but for the ongoing struggle to define what it means to compete as a woman at the highest level of sport.
