The international governing body for swimmers, FINA, announced its decision to ban transgender athletes from competing in women’s elite events and instead plans on creating a working group to establish an “open” category for them in some events as part of its new policy.

Women athletes have become furious over the fact that they’ve trained their entire lives to then have to compete with transgender athletes who were men just a few months ago.

The debate intensified after University of Pennsylvania swimmer Lia Thomas became the first transgender NCAA champion in Division I history after winning the women’s 500-yard freestyle earlier this year.

The new FINA rule would now block Lia Thomas’s participation.

There is one exception, however. The new eligibility policy for FINA competitions states that male-to-female transgender athletes are eligible to compete only if “they can establish to FINA’s comfortable satisfaction that they have not experienced any part of male puberty beyond Tanner Stage 2 (of puberty) or before age 12, whichever is later.”

The new policy would essentially require transgender swimmers to have completed their transition by 12 years old to compete in women’s competitions and maintain their circulating testosterone below the levels of 2.5 nmol/L.

James Pierce, the spokesperson for the FINA president made it very clear that they are not encouraging transitions by the age of 12, but are simply referencing what the scientists are saying about having an advantage if you transition after 12 years old.

“This is not saying that people are encouraged to transition by the age of 12. It’s what the scientists are saying, that if you transition after the start of puberty, you have an advantage, which is unfair,” James Pierce, the spokesperson for the FINA president said.

The policy was passed with a roughly 71% majority after it was put to the members of 152 national federations with voting rights who had gathered for the congress at the Puskas Arena.

“We have to protect the rights of our athletes to compete, but we also have to protect competitive fairness at our events, especially the women’s category at FINA competitions,” said FINA President Husain Al-Musallam.