Under New Olympic Sex Testing Policy, A Cis Woman Who Gives Birth Could Be Considered Male

History is set to repeat itself after the IOC announced a trans ban and mass sex testing for the 2028 Olympics.

Wikimedia Commons // Sam

On Thursday, the International Olympic Committee announced that it would ban transgender women and many cisgender women athletes from competing in women's events and institute mandatory genetic screening of all female athletes. The decision is significant—the Olympics has allowed transgender women to compete since 2004, yet none has ever won a medal, and only a single transgender woman has ever competed: weightlifter Laurel Hubbard of New Zealand, who failed to place at the 2021 Tokyo Games. The ban applies to all sports, including those where no male performance advantage exists, and will require every woman to undergo a genetic test to participate. It will also exclude many cisgender women who produce elevated testosterone due to genetic or medical conditions, such as two-time Olympic champion Caster Semenya. And it is not the first time the Olympics has subjected women to mass sex testing—the last time it did, from 1992 to 1999, the results were disastrous, with cisgender women discovering they had intersex conditions they never knew about, leading to public humiliation, career destruction, and at least one suicide before such testing was abolished.

Under the new policy, every woman seeking to compete in a female event at the Olympics or any IOC competition must undergo a one-time SRY gene screening—a cheek swab or blood test that detects the presence of a gene on the Y chromosome associated with male sex development. The test is similar to the one the IOC abolished 27 years ago after it produced disastrous human consequences. Because the screening identifies the presence of XY genetics, it will target not only transgender women but also intersex people—including cisgender women who carry a genetic condition that some argue makes them "male" despite having been born with a vagina and uterus, raised as girls, and having lived their entire lives as women. In at least 15 documented cases, women with 46,XY karyotypes—the same genetics this test screens for—have successfully carried pregnancies to term and given birth, including women with XY karyotypes that naturally produce testosterone. Under the IOC's new framework, a woman who has been pregnant and delivered a child could be classified as male and barred from competition for failing this test.

Genetic sex testing was introduced at the Olympics in 1992, but it existed for only a short time. In the two Summer Games it covered—Barcelona in 1992 and Atlanta in 1996—over 20 female athletes who were assigned female at birth, had lived their entire lives as women, and had female anatomy were told they were genetically "male" due to conditions they had never known about. The consequences were disastrous. Dr. Myron Genel, a Yale physician who was a prominent critic of the program, reported that the testing was "highly discriminatory" and caused "emotional trauma and social stigmatization" for women with intersex conditions who had been screened out of competition. For athletes from countries where being labeled male could carry severe social or physical consequences, the disclosure was not merely humiliating—it was dangerous. Indian swimmer Pratima Gaonkar died by suicide after her failed sex verification test became public and she was subjected to blackmail attempts; Indian runner Santhi Soundarajan attempted suicide after being stripped of her Asian Games silver medal. The testing was abolished in 1999.

The ban also applies to sports where a male genetic advantage is dubious or nonexistent. In rifle shooting, ESPN reported that women are "as good as, if not fractionally better than, men" in 10m air rifle, and yet these athletes will still have to prove their femininity with a genetic test. In sailing, the competition was mixed for nearly a century at the Olympics, from 1900 to 1988. In archery, men and women shoot the same 70-meter Olympic distance and the world records are extremely close. In December 2025, women's Olympic champion An San exactly matched the men's indoor qualification round record of 599 in Taipei. And outside the Olympics, transgender bans have spread even further—to darts, pool, disc golf, competitive dancing, and even chess.

The scientific evidence, meanwhile, does not support the blanket ban the IOC has imposed. A 2026 meta-analysis published in the British Journal of Sports Medicine—the most comprehensive to date, drawing on 52 studies and nearly 6,500 participants—found that while transgender women on hormone therapy for one to three years retained higher absolute lean body mass than cisgender women, there were no statistically significant differences in upper-body strength, lower-body strength, or aerobic capacity. The researchers concluded that "the convergence of transgender women's functional performance with cisgender women, particularly in strength and aerobic capacity, challenges assumptions about inherent athletic advantages" and that the current evidence "does not justify blanket bans." A separate review in the Journal of Clinical Endocrinology and Metabolism found that after two years of hormone therapy, no advantage was observed for physical performance measured by running time, and that muscle strength corrected for lean mass, hemoglobin, and cardiovascular capacity were no different from cisgender women. No study has demonstrated that transgender women on hormone therapy for more than two years retain a measurable performance advantage in any specific sport.

Some intersex athletes who would be impacted by the decision are already speaking out. Caster Semenya, a two-time Olympic gold medalist, was assigned female at birth in South Africa and has naturally elevated testosterone levels due to a difference in sex development. On Sunday, she expressed her disappointment with IOC President Kirsty Coventry, a fellow African woman and former Olympic swimmer. "Personally, for her as a leader, she's an African, I'm sure she understands how, you know, we as Africans, we are coming from, as a global South, you know, you cannot control genetics," Semenya said at a press conference in Cape Town. "For me personally, for her being a woman coming from Africa, knowing how, you know, African women or women in the global South are affected by that, of course it causes harm.”

“Reintroducing sex testing brings the IOC back to policy that it had discontinued exactly thirty years ago. Back then, they rightfully concluded that sex testing was scientifically inconclusive and caused considerable harm to athletes. Then, in 2021, they approved a Framework on Fairness, Inclusion and Non-Discrimination to best support trans athletes and athletes with sex variations. Now, they are retreating from their own decisions and ignoring the recommendations of various UN bodies, the World Medical Association, and athletes worldwide. But the evidence is clear: sex testing exposes women and girls to privacy violations, public humiliation, and abuse. And it is profoundly discriminatory, too. No one is asking men and boys to undergo these tests. Women and girls shouldn’t either,” said Gurchaten Sandhu, ILGA World Director of Programmes.

The policy takes effect at the 2028 Los Angeles Summer Games and is not retroactive. Affected athletes are expected to bring challenges before the Court of Arbitration for Sport in Lausanne, as Caster Semenya has done with previous eligibility rules. Over 100 civil society organizations, including the Sport & Rights Alliance, ILGA World, and Humans of Sport, have called on the IOC to reverse the decision.