The IOC’s new “Policy on the Protection of the Female (Women’s) Category in Olympic Sport” has been widely discussed for its implications for transgender athletes, but doctors and competitors say its greater impact will fall on people with Differences (or Disorders) of Sexual Development (DSD).
Laurel Hubbard of New Zealand remains the only openly transgender athlete to have competed at the Olympics; the weightlifter failed to record a successful lift in the women’s +87kg at the Tokyo Games. South African double Olympic 800m champion Caster Semenya was prevented from defending her title after World Athletics required women with higher testosterone to lower it below 5 nmol/L for six months—a regulation Semenya refused to follow.
Testosterone levels have long been central to eligibility debates for athletes who do not fit neatly into male or female categories. The IOC policy carves out a narrow exception for athletes with Complete Androgen Insensitivity Syndrome (CAIS) or other rare DSDs who “do not benefit from the anabolic and/or performance-enhancing effects of testosterone.” For other cases it revives SRY testing—a cheek swab method used in the 1990s—to check for the SRY gene on the Y chromosome.
Semenya condemned the approach in a Time article, calling the decision “a disgrace” and arguing: “Genetic screening is not, and never has been, a way to protect girls and women in sports. To call it that is to mask a monster. Let’s call this what it is: exclusion, just with a different name.”
The IOC under former president Thomas Bach previously emphasized there was “no one-size-fits-all solution” to sex and gender testing. A multi-author 2023 scientific report cited by the IOC and others noted that in events depending on endurance, strength, speed and power, men generally outperform women because of sex differences established at puberty—particularly the effects of testosterone.
That biological argument is often deployed in debates about transgender athletes, but specialists say DSD cases are more complicated. DSD describes natural variations in genes, hormones and reproductive anatomy; transgender people, by contrast, are defined by a gender identity that may not align with their sex assigned at birth and may seek medical transition.
Semenya and Algerian-born French boxer Imane Khelif—who won gold at Paris 2024—are both identified as having DSD. Professor Alun Williams, a sports scientist at Manchester Metropolitan University, told the BBC the policy risks further marginalizing these athletes. He warned of serious ethical issues with broad genetic screening, including testing minors and potentially revealing life-changing genetic information. Williams also argued that reducing sex to the presence or absence of a single gene oversimplifies biology, and that evidence of a competitive advantage for people with some forms of DSD remains disputed.
The IOC’s new stance largely aligns with World Athletics’ revised rules. After World Athletics changed its eligibility criteria, Semenya said she felt singled out and stressed that being born with biological differences does not automatically make someone a superior athlete; training, dedication and hard work are decisive.
World Athletics’ earlier rule was introduced under Sebastian Coe. IOC president Kirsty Coventry has defended the IOC’s policy as grounded in science and fairness, saying it aims to prevent biological males from competing in the female category and noting that safety is a concern in some sports. Coventry has said athletes would undergo screening once in their lifetime and be offered education, counselling and specialist medical advice.
Semenya, who said she was invited to provide input when the IOC considered the policy, expressed disappointment in Coventry: “Like me, IOC President Kirsty Coventry is a woman from Africa. I hoped she would be different. Instead, she failed us.”
Edited by: Chuck Penfold