Starting Monday, the world swimming governing body effectively banned transgender women from competing in women’s events.

On Sunday, FINA members overwhelmingly approved a new “gender inclusion policy” that allows swimmers who transitioned before the age of 12 to compete in women’s events. In addition, the organization proposed a “open competition category.”

“This is not to say that people under the age of 12 are encouraged to transition.” “It’s what the scientists are saying, that if you transition after the start of puberty, you have an unfair advantage,” FINA president Husain Al-spokesperson Musallam’s James Pearce told the Associated Press.

“They’re not saying everyone should transition by age 11, that’s ridiculous. You can’t transition by that age in most countries and hopefully you wouldn’t be encouraged to. Basically, what they’re saying is that it is not feasible for people who have transitioned to compete without having an advantage.”

Pearce confirmed that no transgender women are currently competing at the elite level of swimming.

The World Professional Association for Transgender Health recently reduced the recommended minimum age for beginning gender transition hormone treatment to 14 years old, and for some surgeries to 15 or 17 years old.

In addition, FINA’s new 24-page policy proposed a new “open competition” category. According to the organization, “a new working group will spend the next six months looking at the most effective ways to set up this new category.”

According to Pearce, the open competition will most likely result in more events, but the specifics are still being worked out.

“No one quite knows how this is going to work. And we need to include a lot of different people, including transgender athletes, to work out how it would work,” he said. “So there are no details of how that would work. The open category is something that will start being discussed tomorrow.”

At the organization’s extraordinary general congress, members voted 71.5 percent in favor after hearing presentations from three specialist groups — an athlete group, a science and medicine group, and a legal and human rights group — that had been working together to form the policy in response to recommendations made by the International Olympic Committee last November.

The IOC advocated for a shift in focus away from individual testosterone levels and a call for evidence to demonstrate when a performance advantage existed.

FINA’s new policy is “deeply discriminatory, harmful, and unscientific,” and is “not in line with [the IOC’s] framework on fairness, inclusion, and non-discrimination on the basis of gender identity and sex variations,” according to Anne Lieberman of Athlete Ally, a nonprofit that advocates for LGBTQ athletes.

“The eligibility criteria for the women’s category as outlined 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,” Lieberman said.

According to FINA, “some individuals and groups may be uncomfortable with the use of medical and scientific terminology related to sex and sex-related traits, [but] some use of sensitive terminology is required to be precise about the sex characteristics that justify separate competition categories.”

Lia Thomas made history in the United States in March when she became the first transgender woman to win an NCAA swimming championship, the 500-yard freestyle.

Thomas stated on ABC’s “Good Morning America” last month that she aspires to be an Olympic swimmer. She also refuted claims that she has an unfair biological advantage that jeopardizes the integrity of women’s sports, stating that “trans women are not a threat to women’s sports.”

Other sports have been reviewing their policies regarding transgender athletes.

Cycling’s governing body updated its eligibility rules for transgender athletes on Thursday, imposing stricter limits that will force riders to wait longer before competing.

The International Cycling Union (UCI) extended the transition period to two years and lowered the maximum acceptable level of testosterone. The previous transition period was 12 months, but the UCI said recent scientific studies show that “the awaited adaptations in muscle mass and muscle strength/power” among athletes who have made a transition from male to female takes at least two years.