Effective immediately, USA Swimming said a three-person panel of independent medical experts will now decide whether “prior physical development of the athlete as a male” will give an unfair advantage over cisgender females.
The panel will also check that testosterone levels have been less than five nanomoles per liter for at least 36 months prior.
“The development of the elite policy therefore acknowledges a competitive difference in the male and female categories and the disadvantages this presents in elite head-to-head competition.”
It comes as University of Pennsylvania swimmer Lia Thomas, who is transgender, has been smashing records at college events.
She had previously competed on the men’s swimming team at Penn and underwent two years of hormone therapy.
She then went more than 12 seconds faster in the final to set a new program record.
“The process of coming out as being trans and continuing to swim was a lot of uncertainty and unknown around an area that’s usually really solid,” Thomas said.
“Realizing I was trans threw that into question. Was I going to keep swimming? What did that look like?”
It is currently unclear whether Thomas will be able to compete in the upcoming NCAA championships in March under the new policy.
In its statement on Tuesday, USA Swimming cited statistical data which it says shows the “top-ranked female in 2021, on average, would be ranked 536th across all short course yards (25 yards) male events in the country.”
It added: “While recognizing the need for the aforementioned guidelines in elite competition, sport is an important vehicle for positive physical and mental health, and, for this reason, USA Swimming remains steadfast in its continued commitment to greater inclusivity at the non-elite levels.”
It says the policy will stay in place until swimming’s world governing body, Fédération Internationale De Natation (FINA), releases its policy on the matter.
Melissa Alonso and Amy Simonson contributed reporting.