Transgender swimmers who did not transition before puberty have effectively been banned from competing in women’s events, the world swimming governing body announced on Sunday. The International Swimming Federation’s (FINA) new “gender inclusion policy” only allows swimmers who transitioned before the age of 12 to compete in women’s events.

Members of FINA voted 71.5 percent in favor of the new policy after hearing from groups representing athletes, science and medical professionals, and legal and human rights experts.

They will also explore the option of an “open competition category.”

“FINA will always welcome every athlete,” FINA President Husain Al-Musallam said. “The creation of an open category will mean that everybody has the opportunity to compete at an elite level. This has not been done before, so FINA will need to lead the way. I want all athletes to feel included in being able to develop ideas during this process.”

The inclusion of transgender athletes has been a controverial topic in recent years.

Last year, the International Olympic Committee said no athlete should be excluded based on assumed advantages due to gender identity or sex variations.

FINA’s rules come months after University of Pennsylvania Swimmer Lia Thomas became the first transgender woman to win an NCAA swimming title in the 500-yard freestyle.

Thomas began her career on the men’s team as a freshman. Under FINA’s new rules, she would not be permitted to compete in international events.

“The eligibility criteria for the women’s category as it is laid out in the policy (will) police the bodies of all women, and will not be enforceable without seriously violating the privacy and human rights of any athlete looking to compete in the women’s category,” Anne Lieberman of Athlete Ally said in a statement released Sunday.

Last week, the International Cycling Union (UCI) adjusted its rules for transgender athletes. Cyclists will now have to be on low testosterone for two years, up from 12 months. The UCI also lowered the maximum tolerance for testosterone.