Swimming’s world governing body voted to restrict the participation of transgender athletes in women’s events and will look into creating an “open competition” category in a membership vote on Sunday.

FINA members voted 71.5% in favor of a policy that requires transgender swimmers to have completed their transition by age 12 to be able to compete, per the Associated Press. There are 152 national federations with voting rights. The vote applies to all events beginning on Monday. Part of the 24-page policy was a proposal for an “open competition” category.

“I do not want any athlete to be told they cannot compete at the highest level,” FINA president Husain Al-Musallam said. The organization said it is setting up “a new working group that will spend the next six months looking at the most effective ways to set up this new category,” per the AP.

The decision most immediately impacts Penn swimmer Lia Thomas, who became the first transgender NCAA champion in Division I history when she won the women’s 500-yard freestyle in March. Thomas competed on the Penn men’s team before transitioning and competing as a woman for the first time in 2021-22. Thomas met NCAA standards for competition after undergoing testosterone suppression therapy for more than two years.

She has said she wants to continue swimming after college and eyed the 2024 U.S. Olympic trials.

It also restricts NCAA swimmers since the organization said in January it would defer to the national and international bodies’ rulings.

FINA restriction follows IOC recommendations

The vote was taken at FINA’s extraordinary general congress on Sunday from the world championships in Budapest, Hungary. Members heard presentations from three specialist groups that have been working together to form the policy. They consist of an athlete group, a science and medicine group, and a legal and human rights group.

The new path follows recommendations by the International Olympic Committee (IOC) made last November that urged moving away from focusing on individual testosterone levels to asking for evidence to prove when a performance advantage exists. The IOC said no athlete should be excluded based on “unverified, alleged or perceived unfair competitive advantage due to their sex variations, physical appearance and/or transgender status.”

Governing bodies are responsible for regulating their own sports and setting their policies in regards to transgender athlete participation. The cycling governing body updated its rules last week to enact stricter limits that will make riders wait longer to compete.