A cheek swab will now decide who gets to compete as a woman at the Olympics.

The International Olympic Committee announced Thursday that eligibility for female events at the 2028 Los Angeles Games and beyond will be determined by a one-time genetic test screening for the SRY gene — a segment of DNA typically found on the Y chromosome that initiates male sex development. Athletes who test positive for the gene, including transgender women and those with certain differences in sex development, will be barred from the female category.

The policy represents the most significant restructuring of Olympic gender eligibility in decades, replacing the IOC’s previous framework with a biological standard that has divided athletes, human rights experts, and governments along predictable — and some unexpected — lines.

What the new rules actually do

Under the policy, any athlete seeking to compete in a female category event at the Olympics, Youth Olympics, or qualifying tournaments must undergo SRY gene screening via saliva, cheek swab, or blood sample. A negative result — indicating the absence of the gene — permanently satisfies eligibility requirements. A positive result means ineligibility for female competition.

The IOC’s 10-page policy document cites research showing male performance advantages of 10 to 12 percent in most running and swimming events, more than 20 percent in throwing and jumping events, and greater than 100 percent in explosive power sports involving collision, lifting, and punching.

“At the Olympic Games, even the smallest margins can be the difference between victory and defeat,” IOC President Kirsty Coventry said. “So, it is absolutely clear that it would not be fair for biological males to compete in the female category.”

The policy includes a narrow exception for athletes with Complete Androgen Insensitivity Syndrome, who do not benefit from testosterone’s performance-enhancing effects. It does not apply retroactively and explicitly excludes grassroots and recreational sports.

Support from national bodies

The Australian Olympic Committee backed the decision, with president Ian Chesterman calling it a commitment to “fairness, safety and integrity in Olympic competition.”

“This decision provides clarity for elite female athletes who compete at the highest level,” Chesterman said.

Anna Meares, Australia’s chef de mission for LA28 and a two-time Olympic gold medallist, acknowledged the human cost while praising the policy’s clarity.

“I also know the pain this decision will cause some athletes and I empathise with them,” Meares said. “Female athletes know that when they compete it will be fair, it will be safe.”

New Zealand’s Olympic Committee similarly welcomed the “greater clarity, consistency and fairness” the policy would bring.

Human rights concerns

But the policy has drawn sharp criticism from human rights advocates, legal experts, and at least one major government.

France’s sports minister Marina Ferrari called the testing requirement a “step backwards,” noting that similar genetic screening was discontinued in 1999 due to scientific reservations.

“This decision raises major concerns, as it specifically targets women by introducing a distinction that undermines the principle of equality,” Ferrari said. She warned the policy failed to account for the biological diversity of intersex individuals.

LGBTQIA+ advocacy group Pride Cup urged all national sporting bodies to reject the guidelines, warning they would make “all women targets for harassment and abuse.”

“It creates a culture where someone like a coach, an official, or even another parent, feels entitled to question whether your daughter ‘looks female enough’ to belong,” said Nikki Dryden, a Canadian human rights lawyer and 1994 Commonwealth Games bronze medallist. “That is not protecting women’s sport. That is policing girls’ bodies.”

Monash University human rights law expert Paula Gerber said the mandatory testing contravened the International Covenant on Civil and Political Rights, and suggested the decision was influenced by US political pressure.

Athletes caught in the middle

Perhaps no voice carries more weight than Caster Semenya’s. The South African two-time Olympic champion in the 800 metres, who has long faced scrutiny over her natural testosterone levels, was among nine African women athletes who wrote to Coventry before the announcement.

“Consultation means nothing if you have already decided,” Semenya said. “If the IOC had truly listened — if President Coventry had done what evidence-based policy demands — this policy would not exist. It does not smell of science. It smells of stigma. It was not born from care for athletes. It was born from political pressure.”

Dr. Payoshni Mitra, founder of advocacy group Humans of Sport, echoed that criticism, calling the policy “a safeguarding disaster” that appeared driven more by politics than evidence.

The policy’s inclusion of minor athletes — who compete at the Youth Olympics and in qualifying events — has raised particular alarm. Fourteen minors competed at the Paris Olympics, the youngest just 11 years old.

The political backdrop

US President Donald Trump celebrated the decision on Truth Social, calling it a victory for his February 2025 executive order banning transgender athletes from women’s sports.

“This is only happening because of my powerful Executive Order,” Trump wrote.

The IOC policy aligns with World Athletics’ 2023 ban on transgender women who experienced male puberty, and with tightened testosterone regulations that have already reshaped middle-distance running.

Fiona McAnena of UK advocacy group Sex Matters called the IOC’s decision “extremely welcome,” arguing it would set the standard for sports worldwide.

“Women’s sport can only be for those who are female,” McAnena said.

What remains unclear is how this standard will be implemented across the dozens of international federations that govern individual Olympic sports — and whether the human cost acknowledged even by supporters will prompt any reconsideration before the Los Angeles Games begin.

Sources