Transgender swimmer Lia Thomas challenges ban

American swimmer Lia Thomas, who became the first transgender athlete to win a US national college title, is taking legal action in a bid to be allowed to compete again in elite female competition, including the Paris Olympics.

Thomas has not swum since World Aquatics introduced new rules in 2022, which prohibit anyone who has undergone any part of male puberty from competing in the female category. On Friday, the Court of Arbitration for Sport (CAS) confirmed "the registration of the request for arbitration filed by US transgender swimmer Lia Thomas, aimed at challenging certain parts of World Aquatics' Policy on the eligibility for the men's and women's competition categories".

"Ms Thomas accepts that fair competition is a legitimate sporting objective and that some regulation of transgender women in swimming is appropriate," the statement read. "However, Ms Thomas submits that the challenged provisions are invalid and unlawful as they discriminate against her contrary to the Olympic Charter, the World Aquatics Constitution, and Swiss law."

"Such discrimination cannot be justified as necessary, reasonable, or proportionate to achieve a legitimate sporting objective," the 25-year-old added. CAS said that Thomas was seeking "an order from the CAS declaring that the challenged provisions are unlawful, invalid, and of no force and effect". CAS said the proceedings had begun in September 2023, but had been "subject to strict confidentiality rules", adding "at this point, no hearing date has been fixed yet".

Two years ago, the governing body World Aquatics voted to stop transgender female athletes from competing in women's elite races. In February 2022, USA Swimming decided to revise its rules, limiting testosterone levels for a period of at least 36 months for any transgender athletes wanting to compete at the elite level.

The change was prompted by the controversy surrounding Thomas' performance in the university championship. Born male and having begun a transition in 2019, Thomas was adjudged by detractors to be physiologically advantaged.

Barely a month later, the University of Pennsylvania swimmer won the women's 500-yard freestyle final. It was a historic victory, made possible by the refusal of the NCAA, which governs college sports, to apply the new USA federation rules. In June 2022, World Aquatics announced that it wanted to create an open category for transgender athletes. But it limited entry to its women's categories to swimmers who "became women before puberty".