The International Olympic Committee announced a new policy on Thursday that will only allow biological females to compete in women's sports, ahead of the 2028 Los Angeles games.

The policy bans male athletes identifying as females from competing in women's sports, The Hill reported.

According to the policy, eligibility to perform in women’s sports will first be based on SRY gene screening “to detect the absence or presence of the SRY gene,” the IOC said in a statement. The tests determine if the person has a male Y chromosome.

The IOC said that athletes will be screened through their saliva, a cheek swab, or a blood sample, and based on those results, “no athlete with an SRY-positive screen is eligible for competition in the female category at an IOC event.”

“As a former athlete, I passionately believe in the rights of all Olympians to take part in fair competition,” IOC President Kirsty Coventry said in the statement. “The policy that we have announced is based on science and has been led by medical experts.”

“At the Olympic Games, even the smallest margins can be the difference between victory and defeat,” she continued. “So, it is absolutely clear that it would not be fair for biological males to compete in the female category. In addition, in some sports it would simply not be safe.”

“Every athlete must be treated with dignity and respect, and athletes will need to be screened only once in their lifetime. There must be clear education around the process and counselling available, alongside expert medical advice,” Coventry added.

The policy was based on findings from the Working Group on the Protection of the Female Category, which the IOC established to ensure fairness in women’s sports.

The working group’s findings suggested that being born male gives athletes physical advantages, prompting the policy to dictate that “eligibility should therefore be based on biological sex,” according to the IOC.

The new policy will also restrict female athletes with differences in sex development (DSD). Athletes like South African runner Caster Semenya, who was born female but has naturally elevated levels of testosterone in her body, would be restricted from performing. Semenya called the policy change “exclusion with a new name.”

“I have carried this weight. So have other women of color who deserved better from sport,” Semenya told The New York Times. “Reintroducing genetic screening is not progress — it is walking backward.”

"With the rare exception of athletes with a diagnosis of Complete Androgen Insensitivity Syndrome (CAIS) or other rare differences/disorders in sex development (DSDs) who do not benefit from the anabolic and/or performance-enhancing effects of testosterone, no athlete with an SRY-positive screen is eligible for competition in the female category at an IOC event," the committee said.