FINA, swimming’s international governing body, faced backlash over the new "gender inclusion policy" that was approved Sunday setting the standard for transgender athletes’ participation in the sport.

The "gender inclusion policy" will only permit swimmers who transitioned before the age of 12 to compete in women’s events. FINA members voted 71.5% in favor of the new policies. There was also a proposal for a new "open competition policy." The organization said it was 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."

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In the 24-page policy released Sunday, FINA spelled out how transgender men and women will be allowed to compete under the new rules.

LGBTQ+ rights groups and other swimmers said the policy would hurt transgender athletes.

"FINA’s new eligibility criteria for transgender athletes and athletes with intersex variations is discriminatory, harmful, unscientific and not in line with the 2021 IOC principles. If we truly want to protect women’s sports, we must include all women," Athlete Ally, an advocacy group for trans people’s inclusion in sports, wrote in a tweet.

Human Rights Campaign Interim President Joni Madison also spoke out about FINA’s decision.

"This sudden and discriminatory decision is a blatant attack on transgender athletes who have worked to comply with longstanding policies that have allowed them to participate for years without issue. This policy is an example of swimming organizations caving to the avalanche of ill-informed, prejudiced attacks targeted at one particular transgender swimmer. We urge the FINA to rethink its policy and ensure inclusion for all athletes -- including transgender women – and allow them to participate in sports free from discrimination, abuse and harassment," Madison’s statement said.

Jonathan Van Ness at an AIDS event

Jonathan Van Ness was among those who spoke out against FINA's policies. (Jemal Countess/Getty Images)

"To the young athletes who may be disheartened by this policy, know that we know and believe that every young person deserves to be treated with dignity and respect and that transgender kids, like their friends, deserve the same chances to learn sportsmanship, self-discipline, and teamwork, and to build a sense of belonging with their peers."

AUSTRALIAN SWIMMING STAR BACKS FINA'S 'GENDER INCLUSION POLICY'

Others also chimed in on social media.

FINA said transgender men are eligible to compete in FINA competitions and set world records in the men’s category unless:

"For the disciplines of Water Polo and High Diving, the athlete must provide to FINA an assumption of risk form signed and dated by the athlete or if the athlete is a minor, by their legal proxy" or "All athletes who are undergoing treatment involving testosterone or other anabolic substances as part of female-to-male genderaffirming hormone treatment are required to obtain a Therapeutic Use Exemption (TUE) for that treatment in accordance with the FINA Doping Control Rules."

Transgender women and athletes whose legal gender and/or gender identity is female can compete in FINA-sanctioned events if "they can establish to FINA’s comfortable satisfaction that they have not experienced any part of male puberty beyond Tanner Stage 2 or before age 12, whichever is later."

Lia Thomas Upenn nationals

Lia Thomas looks on after winning the Women's 500 Yard Freestyle during the 2022 NCAA Division I Women's Swimming & Diving Championship at the McAuley Aquatic Center on the campus of the Georgia Institute of Technology on March 17, 2022 in Atlanta, Georgia. (Mike Comer/NCAA Photos via Getty Images)

The athlete must produce evidence they have "complete androgen insensitivity and therefore could not experience male puberty" or "They are androgen sensitive but had male puberty suppressed beginning at Tanner Stage 2 or before age 12, whichever is later, and they have since continuously maintained their testosterone levels in serum (or plasma) below 2.5 nmol/L" or "An unintentional deviation from the below 2.5 nmol/L requirement may result in retrospective disqualification of results and/or a prospective period of ineligibility or "An intentional deviation from the below 2.5 nmol/L requirement may result in retrospective disqualification of results and a prospective period of ineligibility equal or commensurate in length to periods imposed under the FINA DRC for intentional anti-doping rule violations involving anabolic steroids."

Transgender athletes who do not meet the eligibility standards may compete in "any open events" the organization could develop in the future.

David Gerrard, FINA’s top medical official, said Monday that the international governing body for elite swimming’s new policy on transgender athletes was the "best outcome" for the future of the sport.

"To my mind, FINA’s approach to this was very enlightened, it was very balanced, it was informed," Gerrard told Reuters. "It recognized the athlete’s voice, the scientific, objective evidence and the somewhat more subjective, human rights (and) legal issues which were argued very forcefully by the lawyers present.

FINA logo in 2009 in Rome

A logo of the is the international governing body of swimming, diving, water polo, synchronized swimming and open water swimming, FINA is displayed during the FINA World Championships in Rome on July 25, 2009.  (MARTIN BUREAU/AFP via Getty Images)

"I hope that that model is something that's considered by other sports."

Gerrard, a former New Zealand Olympian, added fairness in the sport was a main issue FINA was trying to confront and predicted it will still be an issue.

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"It is an issue that we’re going to have to confront, and the debate is going to continue," he said. "But when it comes to fairness and when it comes to safety, you’ve got to draw a line in the sand."