Idaho families with transgender children are seeking to stop the state’s ban on gender-affirming care for trans minors — which threatens health care providers with felony charges and prison — from going into effect.

The families had already sued to challenge the ban, but Friday they filed a motion asking a federal court to issue a preliminary injunction to keep it from going into effect while the case is heard. It is set to become effective January 1. The motion was filed in U.S. District Court in Idaho.

The families and their attorneys, including lawyers from the American Civil Liberties Union and other groups, say the ban violates the U.S. Constitution and that letting it be enforced will cause irreparable harm to trans youth.

“There is no justification for banning all gender-affirming medical care for young Idahoans with gender dysphoria,” Leo Morales, executive director of the ACLU of Idaho, said in a press release. “The ban prohibits care that the youth, their parents, and their doctors all agree is medically necessary, and which is supported by every major medical association in the U.S.”

Republican Gov. Brad Little signed the ban into law in April, deeming any such care a felony punishable with up to 10 years in prison. It covers not only surgery — genital surgery is not recommended for minors anyway — but puberty blockers and hormone therapy if they are prescribed for the purpose of gender transition. The treatment is allowed for cisgender minors for conditions such as early-onset puberty, illnesses, or injuries.

That violates the U.S. Constitution’s guarantee of equal protection of the laws, plus parents’ right to make decisions about their children’s heath care, says the suit, Poe v. Labrador, which was filed June 1 in the same district court.

Plaintiffs in the suit are two trans teens, identified by the pseudonyms Jane Doe and Pam Poe, and their parents. They are represented by the national ACLU, its Idaho affiliate, and the law firms W/rest Collective; Paul, Weiss, Rifkind, Wharton & Garrison LLP; and Groombridge, Wu, Baughman & Stone LLP. Named as defendants are Idaho Attorney General Raúl Labrador; Jan M. Bennetts, county prosecuting attorney for Ada, Idaho; and members of the Idaho Code Commission.

“Last month, in the first ruling on the merits on such a case, a federal judge in Arkansas permanently struck down a ban on gender-affirming health care for minors, finding the ban violated the constitutional rights of transgender youth, their parents, and their doctors,” Ritchie Eppink, an attorney with W/rest Collective, said in the release. “We hope the court will rule in our favor in this case and prevent this kind of discriminatory harm from reaching Idaho families.”

Bans have been blocked while cases are heard in Alabama, Florida, Indiana, and Kentucky, while in a suit in Oklahoma, the state and the challengers have agreed that the law will not be enforced while the case proceeds. A district court had blocked Tennessee’s ban, but an appeals court recently lifted that injunction. Suits have been filed in several other states.

The Idaho law “is part of a troubling trend across the country that targets trans people and access to necessary medical care such as abortion and gender-affirming hormones,” Li Nowlin-Sohl, senior staff attorney with the national ACLU’s LGBTQ & HIV Project, said in the release. “We are deeply concerned with the coordinated attacks on people’s rights to access health care free from government intrusion.”