The national governing body for competitive swimming issued a new policy on Tuesday establishing eligibility criteria for transgender athletes competing in elite events.

NCAA athletes will not be impacted by the change — unless the agency decides to adopt the new policy later this month.

For now, that means University of Pennsylvania swimmer Lia Thomas can still compete in the upcoming championships. Thomas is a 22-year-old trans woman who has been breaking collegiate swim records and making waves across the sports world: Critics, conservative media outlets, and even some of her teammates’ parents are claiming her male-at-birth assignment gives her an unfair advantage. Thomas, who has been on gender hormone therapy for more than two years, has followed all NCAA eligibility requirements.

» READ MORE: Penn swimmers issue statement supporting Lia Thomas

Effective immediately, USA Swimming will now require trans women athletes to submit an application to compete to a three-person panel of “independent medical experts,” who will determine whether “prior physical development of the athlete as a male” gives the athlete “a competitive advantage over the athlete’s cisgender female competitors.”

The swimmer must also show that their testosterone levels have been less than 5 nanomoles per liter continuously for at least 36 months.

But USA Swimming’s policy applies only to elite events and USA Swimming athlete members.

NCAA events are not considered elite events and Thomas is not a member athlete, said USA Swimming spokesperson Isabelle McLemore.

McLemore said that whether this policy applies to Thomas is an NCAA decision, “as they will decide what policy they implement and how they adjudicate it.”

NCAA spokesperson Gail Dent said that the Committee on Competitive Safeguards and Medical Aspects of Sports “will review this change at its next meeting and will make recommendations as it deems appropriate to the NCAA Board of Governors,” as is consistent with NCAA policy. That meeting will be held later this month, Dent said.

The debate over transgender athletes’ right to participate in sports has intensified, especially in college sports, following the success of Thomas, a trans woman who swims freestyle.

» READ MORE: Lia Thomas swims on for Penn amid controversy

Thomas competed for the Penn men’s team for three seasons, before beginning her medical transition in May 2019. She underwent more than two years of hormone replacement therapy, submitted eligibility paperwork to the NCAA, and then joined the women’s team this season.

Thomas holds this year’s fastest time in the nation as a female college athlete for the 200- and 500-meter freestyle events. She’s an NCAA championship favorite.

“We continue to work with the NCAA regarding Lia Thomas’ participation in the 2022 NCAA Swimming and Diving Championship,” Penn athletics spokesperson Steve Cunha said in a statement.

Most sports governing body policies require an athlete to undergo 12 to 24 months of hormone therapy, said Joanna Harper, who is researching transgender athletic performance at Loughborough University in England.

USA Swimming’s policy is the first to require three years, she said.

“There is no good scientific reason to require 36 months of hormone therapy,” Harper said.

Christina Roberts, physician of adolescent medicine at Children’s Mercy Kansas City, who studied the fitness tests of transgender members of the Air Force before and after beginning hormone therapy, said the panel is a good start, and that there should be some individualized basis to determining eligibility.

But, she said, the panel has no evidence to reference.

“Your fate is really up to a panel of experts nominated by somebody else, who have no evidence to guide their decisions,” she said.

Roberts’ study found that after trans women took two years of feminizing hormones, their fitness and endurance levels were the same as the average cis woman’s, though their run times remained a bit faster.

Thomas started taking testosterone suppressants and estrogen supplements in May 2019. By the NCAA championships in March, Thomas will have undergone 34 months of testosterone therapy. If the NCAA adopts USA Swimming’s policy, she will be ineligible to compete.

“I can see no other compelling reason to put a 36-month limit in there except to exclude Lia Thomas,” Harper said. “I think it’s despicable.”

Thomas’ fate is now in the hands of the NCAA.

Last month, the NCAA revised its policy on transgender athletes’ eligibility. Now, instead of a uniform policy across all sports, the NCAA will use the policy of each sports’ national governing body, meaning eligibility requirements will vary by sport.

If a sport’s national governing board lacks a policy, it would be determined by the policy of its international federation. If there is no international federation policy, it would be determined by the International Olympic Committee policy criteria, which requires the athlete’s total testosterone level be below 10 nmol/L for at least 12 months prior to their first competition.

The NCAA is implementing the new policies in phases. For 2022 winter sport championships, like swimming, trans athletes must submit documentation showing they’ve undergone one year of testosterone suppressant treatment, and prove their testosterone levels are below 10 nmol/L, four weeks before the championship.

For now, Dent said in an email, “the current NCAA transgender student-athlete participation policy adopted Jan. 19 remains in effect.”

USA Swimming said its policy would remain in place until FINA — the international governing board for swimming — releases its policy on the matter.

Athletes must abide by the policy to be eligible to set USA Swimming national age-group records in the 13-14 category and above, along with American records. USA Swimming’s definition of “elite events” includes FINA events, the Pan Pacific Championships, World University Games, USA Swimming Nationals, Junior Nationals, U.S. Open, International Team Trials, and the U.S. Olympic Team Trials.

“USA Swimming has and will continue to champion gender equity and the inclusivity of all cisgender and transgender women and their rights to participate in sport, while also fervently supporting competitive equity at elite levels of competition,” it said in a statement.

The statement lists statistical data about how top-ranked female swimmers would rank in male swimming competitions. It does not include any medical or scientific evidence supporting its policy, though the statement notes it followed “several months of internal work, critical stakeholder discussions, and medical and legal review.”

Thomas swam on the Penn men’s team for two years, before realizing she was trans in 2018, she has said. She was worried about how coming out would impact her ability to continue swimming, she said in a previous interview with SwimSwam.

“I was struggling; my mental health was not very good. It was a lot of unease, basically just feeling trapped in my body. It didn’t align,” she said. “I decided it was time to come out and start my transition.”

She came out to her teammates that fall. She continued competing on the men’s team that season, while taking the suppressants.

Thomas began submitting all of her medical proof and paperwork to the NCAA in summer of 2020, and was approved for eligibility. She did not swim at all last year, as the Ivy League season was canceled by the coronavirus pandemic. This is her first season on the women’s team.

Thomas and her teammates are set to compete in the Ivy League championships at Harvard in two weeks. The NCAA championships, for which Thomas already qualified, are in mid-March.