The International Olympic Committee announced on Thursday that transgender women and athletes with differences of sex development (DSD) will be barred from competing in the women’s category at future Olympic Games. The rule takes effect at the 2028 Summer Olympics in Los Angeles.
The decision, announced by IOC president Kirsty Coventry, reverses a 2004 policy that had allowed transgender athletes to compete provided they met certain testosterone thresholds. Under the new framework, any athlete wishing to compete in the women’s category must undergo a one-time screening for the SRY gene — the gene responsible for male sex development — via a saliva sample, cheek swab, or blood test.
“As a former athlete, I passionately believe in the rights of all Olympians to take part in fair competition,” said Coventry, herself a decorated Olympic swimmer from Zimbabwe and the first woman to lead the IOC. “It is absolutely clear that it would not be fair for biological males to compete in the female category. In addition, in some sports it would simply not be safe.”
What the Science Says — and Doesn’t Say
The IOC’s 10-page policy document lays out its justification in stark terms. It states that male athletes hold a 10 to 12 percent performance advantage in most running and swimming events, a figure that will resonate immediately with competitive runners. In throwing and jumping events, it puts that advantage above 20 percent. In explosive power sports — weightlifting, collision sports, and boxing — the document says the gap can exceed 100 percent.
Crucially, the IOC argues that these advantages persist even after testosterone suppression or gender-affirming hormone treatment.
But the science is not settled. A 2024 study funded in part by the IOC itself directly challenged the idea that transgender women retain a meaningful competitive edge, and cautioned against blanket bans. The IOC did not cite specific studies in its new policy, and has declined to name the members of the working group that developed it. Several researchers whose work has cast doubt on the competitive advantage argument told USA TODAY Sports in September that they were not consulted.
This debate is not new to track and field. World Athletics introduced mandatory genetic testing for female athletes back in March 2025, making it the first major sport to require SRY gene screening — the IOC is now following suit at the Olympic level.
A Decade of Controversy Comes to a Head
Sports governing bodies have been grappling with this issue for years, but the debate has been most visible in track and field and boxing. World Athletics was among the first major federations to prohibit transgender women from competing in the female category, a move that foreshadowed Thursday’s sweeping Olympic ruling.
For runners, the central figure has long been Caster Semenya. The South African middle-distance runner burst into public view in 2009 when she won the 800 meters at the World Championships, triggering a wave of controversy over her appearance and testosterone levels. She went on to win Olympic gold in the 800m in both 2012 and 2016. After years of legal battles, Semenya ended her seven-year legal battle over sex eligibility rules having been effectively shut out of elite competition under testosterone regulations since 2019.
Semenya was among nine African athletes who sent a letter to Coventry ahead of Thursday’s announcement, detailing what they described as “cruel and degrading treatment” — including invasive examinations, forced surgeries, and harmful hormone treatments — resulting from eligibility regulations targeting women with natural sex variations.
In a statement to the New York Times, Semenya did not hold back. “I have carried this weight. So have other women of color who deserved better from sport,” she said. “Reintroducing genetic screening is not progress — it is walking backward. This is just exclusion with a new name.”
At the 2024 Paris Olympics, the issue exploded again when boxers Imane Khelif of Algeria and Lin Yu-ting of Taiwan — both women who had competed internationally for years — became the subject of an intense and often hostile public debate about their eligibility. Both went on to win gold. Just this week, boxing officials cleared Lin to compete at the Asian Boxing Championships, her first international event since Paris.
World Athletics had already moved to require SRY gene testing for female athletes ahead of Tokyo 2025, setting a precedent that the IOC has now extended across all Olympic sports.
