The ruling applies only to two transgender girls whose parents filed a lawsuit challenging the law.
The lawsuit alleges the law violates the equal protection clause in the U.S. Constitution and Title IX. The appeals court says the challengers are likely to succeed on the equal protection claim, but the court did not say whether it thought the Title IX claim also would prevail.
The lawsuit will be sent back to the lower court, and the law will remain blocked while the case is litigated.
“We always expected to win this case in the U.S. Supreme Court," Tom Horne, Arizona's superintendent of public instruction, said Tuesday. “The 9th Circuit is notoriously left wing. We did not expect to get a fair hearing in the 9th Circuit.”
Rachel Berg, an attorney for National Center for Lesbian Rights, which represents the girls and their parents, said the ruling “recognizes that a student’s transgender status is not an accurate proxy for athletic ability and competitive advantage.”
Arizona is one of several states and some school districts that have passed laws limiting access to school sports teams or other facilities to students on the basis of the sex they were assigned at birth rather than their gender identity. The ruling on its law came a day before a federal judge said that two transgender girls in New Hampshire can try out for and play on girls school sports teams while the teens challenge that state's ban.
Officials in Arizona have said its lawpasses federal muster because it aims at fairness.
LGBTQ+ rights advocates say such measures are anti-transgender attacks disguised as protections for children and that they use transgender people as political pawns to galvanize GOP voters.
At least 26 states have adopted laws in recent years banning transgender girls and women from some girls and women's sports competitions. The policies face court challenges. Besides Arizona, enforcement of the laws has been put on hold by judges in Idaho, Ohio and Utah. Enforcement is also barred regarding some specific athletes in other states.
The measures are part of broader efforts to restrict the rights of transgender people, particularly students. States also have laws barring gender-affirming healthcare for minors, restricting which school bathrooms can be used and requiring schools not notify parents about their students’ pronoun requests.