WASHINGTON, United States (AFP) — The United States (US) Supreme Court on Tuesday wades into the hot-button issue of transgender athletes in girls’ and women’s sports.

The conservative-dominated court is to hear challenges to state laws in Idaho and West Virginia banning transgender athletes from female competition.

More than two dozen US states have passed laws in recent years barring athletes who were assigned as male at birth from taking part in girls’ or women’s sports.

The Idaho case to be heard by the nine justices stems from the Republican-led state’s 2020 “Fairness in Women’s Sports Act.”

The act was challenged by a transgender athlete at an Idaho university, and lower courts ruled that it violates the equal protection clause of the US Constitution.

West Virginia’s 2021 Save Women’s Sports Act was challenged by a middle school student who was not allowed to compete for the girls’ track team.

An appeals court ruled that the ban amounted to discrimination on the basis of sex and violated Title IX, the federal civil rights law which prohibits sex-based discrimination in educational programs.

Last February, President Donald Trump issued an executive order aimed at banning transgender athletes from girls’ and women’s sports after campaigning for the White House on the issue.

“From now on women’s sports will be only for women,” Trump said. “With this executive order, the war on women’s sports is over.”

The executive order allows federal agencies to deny funding to schools that allow transgender athletes to compete on girls’ or women’s teams.

University of Pennsylvania swimmer Lia Thomas became a lightning rod in the debate over transgender athletes in women’s sports after competing in female collegiate meets in 2022.

Critics and some fellow swimmers said Thomas, who had earlier swum on UPenn’s men’s team, should not have been allowed to compete against women due to an unfair physiological advantage.

UPenn eventually agreed to ban transgender athletes from its women’s sports teams, settling a federal civil rights complaint stemming from the furor around Thomas.

The move followed an investigation by the Education Department’s Office for Civil Rights which found the university had violated Title IX by allowing Thomas to compete in women’s competitions.

Conservatives outnumber liberals six to three on the Supreme Court, and the justices weighed in on two high-profile transgender cases last year.

They upheld a Tennessee state law banning gender-affirming medical treatment for transgender minors and backed a move by Trump to have transgender troops dismissed from the military.

The Supreme Court is expected to rule in June or early July.