A federal appeals court on Thursday upheld a decision blocking Idaho’s first-in-the-nation ban on transgender athletes in girls and women’s sports.

A three-judge panel of the 9th U.S. Circuit Court of Appeals upheld a judge’s preliminary injunction against the 2020 law, which would prohibit transgender women and girls from playing on female sports teams sponsored by public schools, colleges and universities.

The judges ruled that the ban discriminates not just against transgender women but all women, citing a provision in the law that allows for anyone to dispute the sex of a female student athlete in Idaho. That provision would require the athlete to verify their gender through medical procedures, including gynecological exams.

The court said the law “perpetuates historic discrimination against both cisgender and transgender women by categorically excluding transgender women from athletic competition and subjecting all women to an invasive sex dispute verification process.”

The ruling follows a historic wave of new state laws around the country restricting the rights of transgender people, especially trans youth. More than 20 states have enacted similar sports restrictions since Idaho’s Republican lawmakers in North Carolina on Wednesday enacted the latest sports restriction, overriding Democratic Gov. Roy Cooper’s veto of that measure and two other bills targeting the rights of transgender youth.

“Idaho’s ban and all others like it are designed to alienate and stigmatize transgender people and we’ll never stop fighting until all transgender youth are given the equal playing field they deserve,” said Chase Strangio, deputy director for transgender justice at the American Civil Liberties Union’s LGBTQ & HIV Project.

The ACLU challenged the ban on behalf of Lindsay Hecox, a transgender student at Boise State University who had been planning to try out for cross country and play club soccer. A cisgender high school athlete had also challenged the ban over its “sex verification” testing provision.

A federal judge blocked the law in 2020. Idaho Gov. Brad Little signed the measure, passed by Republicans during the 2020 state legislative session, into law despite warnings from legal experts that it wasn’t likely to survive court challenges. Little’s office and the state attorney general’s office did not immediately respond to messages Thursday afternoon.

Supporters of the bans have said they are needed to provide an equal playing field and to protect female athletes’ access to scholarships. But the appeals court said there was no evidence of a transgender woman receiving an athletic scholarship over a cisgender woman in Idaho.

A proposed rule unveiled by the Biden administration in April would forbid schools from enacting outright bans on transgender athletes but would allow teams to create some limits in certain cases. The proposal has drawn outrage from conservatives. But it also angered trans rights supporters, who note it would prevent some transgender athletes from competing.