The women’s category of Olympic sports will be limited to biological females from 2028.

The International Olympic Committee (IOC) says eligibility will be determined by a “once-in-a-lifetime” sex test, which would prevent transgender women and those with differences in sexual development (DSD) who have gone through male puberty from competing.

It will take effect from the Los Angeles Olympics.

IOC president Kirsty Coventry said the policy was “led by medical experts”.

“At the Olympic Games even the smallest margins can be the difference between victory and defeat,” she said.

“So 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.”

The IOC said eligibility for the female category would be determined by a screening to detect the SRY gene – the sex-determining region Y gene – which is part of the Y chromosome and causes male characteristics to develop.

“The IOC considers that SRY gene screening via saliva, cheek swab or blood sample is unintrusive compared to other possible methods,” it said.

“Athletes who screen negative for the SRY gene permanently satisfy this policy’s eligibility criteria for competition in the female category.

“Unless there is reason to believe that a negative reading is in error, this will be a once-in-a-lifetime test.”

The IOC said athletes who fail the test would “continue to be included in all other classifications for which they qualify. For example, they are eligible for any male category, including in a designated male slot within any mixed category, and any open category, or in sports and events that do not classify athletes by sex.”

Until this announcement, the IOC left sex eligibility regulations to the governing bodies of individual sports, rather than applying a universal approach.

While athletics, swimming, cycling and rowing have brought in bans, many others allowed transgender women to compete in female competition if they lowered their testosterone levels.

New Zealand’s Laurel Hubbard became the first openly transgender women to compete at an Olympics after being selected for the women’s weightlifting team at Tokyo 2020.

But by the Paris 2024 Games, there were not known to be any transgender women competing in the women’s section due to the bans.

There was, however, controversy in the boxing after Algeria’s Imane Khelif won the women’s welterweight boxing gold medal, a year after being disqualified from the World Championships for reportedly failing a gender eligibility test.

Some reports took the IBA saying Khelif has XY chromosomes to speculate that the fighter might have DSD. However, the BBC was not able to confirm whether this was or was not the case. Khelif has always insisted she is a woman and told CNN earlier this year that she would take a sex test to compete at LA 2028.

The IOC’s ban will also cover almost all athletes with a DSD.

The Guardian reported in September that between 50 and 60 athletes who went through male puberty had been finalists in the female category in global and continental track and field championships since 2000.

This is a rare condition in which a person’s hormones, genes and/or reproductive organs may be a mix of male and female characteristics.

Two-time Olympic women’s 800m champion Caster Semenya’s DSD means she has male XY chromosomes.

Previously, DSD athletes who had been through male puberty could compete in women’s sport, provided they kept their testosterone within certain levels.

There is an one exemption in the policy for DSD athletes with a rare condition – complete androgen insensitivity syndrome (CAIS), which means they have not gone through male puberty.

‘A hugely significant decision’ – analysis

This is a hugely significant decision by the IOC following years of controversy over the participation of transgender and DSD athletes in female competition, and intense debate over how sports should balance fairness and safety with inclusion.

In a reflection of just how sensitive an area of policy this has become, the IOC has traditionally left it to international sports to decide on eligibility criteria for female competition. But in a major shift in policy, all federations will now be expected to follow suit.

A blanket ban on transgender athletes and DSD athletes from women’s sport will be welcomed by many who have long felt that such a move is essential if fairness and safety in the female category is to be preserved.

Supporters say this approach – based on a genetic test – has recently been successfully employed in athletics and boxing, and is a reliable, confidential and proportionate approach that has the backing of sports scientists, along with the vast majority of athletes.

They also say this method is more humane than requiring transgender or DSD athletes to suppress their natural testosterone levels, and will avoid the intense media scrutiny that some athletes have been subjected to.

Opponents remain concerned, however, that the approach is invasive, and that there is a risk of accidental contamination and a potential false positive.

This month a group of academics called sex testing a “backwards step and a harmful anachronism” in a report submitted to the British Journal of Sports Medicine, and that testing violates the human rights of athletes and could create stigma and psychological distress.

They said it was “a simplistic way of reducing a characteristic to a single gene, which does not reflect the complex nature of sex”.

The IOC used the SRY gene test in the 1980s but, after a number of ‘false positives’, and fears that female athletes were being punished for natural variations, sex verification tests were abolished in the 1990s.

Now, under mounting pressure, sport’s most powerful body has embarked on a new approach, and it will be fascinating to see if it now faces any legal challenges.

How the IOC reached its decision

The IOC said its working group reviewed the latest scientific evidence over the past 18 months, which it said showed a “clear consensus” that “male sex provides a performance advantage in all sports and events that rely on strength, power and endurance”.

It consulted a "wide range of experts in relevant fields” and an online athlete survey that had more than 1,100 responses.

Interviews were also conducted with “impacted athletes from around the world”.

The IOC said: “Feedback from the athlete consultation revealed that, although nuances exist across sex and gender, region and athlete status (active/retired), there was a strong consensus that fairness and safety in the female category required clear, science-based eligibility rules, and that protecting the female category is a common priority.”

The move does not apply to any grassroots or recreational sports programmes, and the IOC said the findings of any tests would not be applied retrospectively.

Coventry said: “Every athlete must be treated with dignity and respect, and athletes will need to be screened only once in their lifetime.

“There must be clear education around the process and counselling available, alongside expert medical advice.”

Reaction to the IOC decision

A World Athletics spokesperson said: “We have led the way in protecting women’s sport over the last decade. Attracting and retaining more girls and women into sport requires a fair and level playing field where there is no biological glass ceiling. This means that gender cannot trump biology. A consistent approach across all sport has to be a good thing.’’

Fiona McAnena, director of campaigns for sex-based rights charity Sex Matters: “Sex Matters welcomes the news that the International Olympic Committee has finally done the right thing. Women have been cheated of medals and of fairness in sport for years. Males never should have been allowed into the women’s category, whether they’re beginners or elite, young or old.”

Su Wong of the campaign group SEEN in Sport: “Protecting the female category doesn’t just matter for our Olympic athletes. It impacts ordinary women and girls who just want fair and safe sport. For over a decade, international and national sporting bodies have relied on IOC policy to justify males in the female category. This justification ends today.”

Caster Semenya: “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. As a woman from Africa, I had hoped President Coventry would be different. I had hoped she would listen to all of us — not just the powerful, not just the comfortable. She had the chance. She failed us.”

Transgender and DSD athlete controversies

In recent years a growing number of sports federations, including World Aquatics and World Athletics, have barred athletes who have undergone male puberty from competing in elite female competition amid concerns over fairness and safety.

Last May the Football Association and England and Wales Cricket Board were among a number of British sports bodies to follow suit after the UK Supreme Court’s ruling that the legal definition of a woman was based on biological sex.

The moves have been opposed by trans rights campaigners who argue they could violate human rights, and insist inclusion should be prioritised.

However, this year US President Donald Trump signed an executive order that prevents transgender women from competing in female categories.

He said it would include the 2028 Olympics and that he would deny visas for transgender athletes trying to visit the US to compete at the Games.

At the 2020 games, Hubbard failed to record a successful lift in the women’s +87kg weightlifting.

Four year later, the IOC cleared 25-year-old Khelif to compete, along with Taiwan’s Lin Yu-ting, who was also banned by the suspended International Boxing Association (IBA).

The IOC said competitors were eligible for the women’s division if their passports said they were female.

Last week it was announced that Lin could return to women’s sport after passing a sex test.

At the 2016 Olympics in Rio, all three medallists in the women’s 800m, including winner Semenya, were DSD athletes, intensifying calls for tighter rules.

World Athletics then insisted that for track events from 400m up to the mile, DSD athletes must reduce their testosterone levels in order to be eligible.

Semenya refused, arguing it was an infringement of her human rights and discriminatory.

Amid a long legal battle, World Athletics’ made its rules stricter in 2023. (BBC)

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