Hardly any victory is as controversial as this one: This year, swimmer Lia Thomas became the first trans athlete to win a title in the highest category of the National Collegiate Athletic Association (NCAA), making history.

But the success of the American quickly became a political issue. She was accused of unfair advantages and fraud, and Florida Gov. Ron DeSantis even claimed she would destroy the women’s category – apparently with success.

Because now the World Swimming Federation (Fina) has drawn consequences and announced a corresponding regulation on Sunday: According to this, trans women are only allowed to compete with women if they have completed gender reassignment measures by the age of twelve. Specifically, the 24-page resolution states that trans women are only eligible to compete in the women’s category if “they can demonstrate to Fina’s satisfaction that they have not passed any part of male puberty beyond Tanner Stage 2 or before the age of 12, whichever comes later,” have experienced.

From then on, their testosterone levels must have been consistently maintained below 2.5 nmol/L, because even an “unintentional deviation” from these values ​​can result in retrospective disqualification or suspension.

The resolution was passed with 71% of the votes from 152 national federations at the World Championships in Budapest last weekend. Fina President Husain al-Musallam said: “We must protect our athletes’ right to compete, but we must also uphold competitive fairness in our events, particularly in the women’s category of Fina competitions.”

In addition to the new regulation, a working group is to be set up in the future to take care of an “open category” for people who “do not meet the criteria for the male or female category”.

After the regulation was published, a heated debate broke out on social media: Ex-Olympic champion Nancy Hogshead-Makar, who had spoken of “unfair advantages” in recent months, supported the decision, and former British swimmer Sharron Davies also wrote on Twitter: “I can not say how proud I am of my sport, Fina and the Fina President, because they do science, interview athletes and coaches and work for fair sport for women.”

Kalle Hümpfner from the Federal Association of Trans *, however, criticizes the decision: “The new regulation puts a lot of pressure on young trans girls. They have to make decisions early on if they want to get into professional competitive sports.” It is unrealistic to fully complete a medical transition before the age of 12. “In Germany, no operations are performed on trans adolescents in the genital area at this age; this is a phase in which measures such as puberty blockers or hormone therapy are in the foreground.”

And even in this area, the hurdles are very big, so that only a few young people have access. All in all, the new rules mean that trans women will be effectively excluded from many important swimming competitions in the future.

Hümpfner says that each person should decide at their own pace which gender reassignment measures should be implemented. “It is not necessary for trans women or girls to undergo all currently possible surgeries to be recognized as female.”

The regulation rather contradicts the international trend: At the beginning of the year, the International Olympic Committee presented a new regulatory framework according to which there is no longer a uniform testosterone level that trans athletes have to fall below in order to be admitted to competitions. The World Athletics Federation, on the other hand, stipulates that athletes must not exceed a testosterone level in the blood of five nanomoles per liter of blood. In comparison, Fina has set the limit value relatively low.

Scientific studies have long shown that athletes with higher testosterone levels do not have an advantage per se. Correcting a study published in the British Journal of Sports Medicine, the authors wrote that the link between testosterone levels and athletic performance could not be proven. Hümpfner also points out: “Performance advantages in sports are determined by many factors: physique and the span of the arms, for example, have a great influence on how successfully a person can swim. It is therefore a shortcut to refer solely to gender and determine putative performance advantages for trans women.”

But although supposed advantages cannot be proven, there have been repeated attempts in the past to exclude trans women from women’s teams. In 2020, for example, the World Rugby Federation wanted to ban trans women entirely from women’s teams, citing safety concerns and physical advantages as the reason for the decision.

Last year, weightlifter Laurel Hubbard became the first trans athlete in history to compete in the Olympics and faced discriminatory hostility even before the Games began.

And just last week, the World Cycling Federation tightened the conditions for participation for trans women by lowering the maximum value for testosterone levels from five nanomoles per liter to 2.5 and the time limit in which this value may not be exceeded from twelve to 24 months.

However, the creation of a separate category for trans athletes in swimming is a novelty. Hümpfner finds the decision problematic “because it represents something special”. It is also unclear whether the group will ever be large enough for competitions to take place. “Trans people generally do less sport, both in amateur and competitive sports, because the inhibition threshold is very high to go into an area in which genders are separated and bodies are strongly standardized.”

For example, many trans people report major hurdles preventing them from doing sport and discriminatory comments during the transition. “Policies like Fina’s are an additional deterrent to trans people,” says Hümpfner.

The extent to which Fina actually organizes its own competitions for trans people remains to be seen. In any case, Lia Thomas is not allowed to take part in any competitions for the time being due to the regulations – not even at the Olympic Games in Paris, which were actually her big goal.