BOISE, Idaho (AP) — An Idaho law restricting which bathrooms transgender students can use in schools will go into effect while a court challenge plays out.

Chief U.S. District Judge David Nye on Thursday denied a request by a plaintiff who is challenging the law to keep it from being enforced until the lawsuit is resolved, The Idaho Statesman reported. In August, Nye had placed the law on hold in August pending his decision.

The law will go into effect 21 days after his ruling.

It prohibits transgender students from using public school restrooms and locker rooms that align with their gender identity. It also allows other students to sue their school if they encounter a student using a bathroom that doesn’t align with their sex assigned at birth.

Nye said the plaintiff failed to show their challenge would succeed. He noted the law is “substantially related to the government’s important interest in protecting the privacy and safety of students” while using a restroom or a changing room.

Lambda Legal, which represents LGBTQ+ people in lawsuits, sued the state in July on behalf of an Idaho transgender student, arguing that the law known as Senate Bill 1100 unconstitutionally discriminates against students based on their gender identities.

“Although it likely comes as little solace to Idaho’s transgender students who, as a result of the court’s decision today, may have to change their routines, or who, regrettably, may face other societal hardships, the court must stay within its lane,” Nye wrote. “Its duty is to interpret the law; it is not a policy-making body.”

The judge also denied the state’s request to dismiss the case, saying state attorneys sought to dismiss all of the lawsuit’s claims in a “perfunctory manner, with little explanation.”

School districts in Idaho currently regulate which bathrooms transgender students may use. About a quarter of Idaho schools allow transgender students to use restrooms and locker rooms that align with their gender identity, Nye said in a previous decision.

Thursday’s ruling puts transgender students directly in harm’s way by stigmatizing them as outsiders in their own communities and depriving them of the basic ability to go about their school day like everyone else, Peter Renn, Lambda Legal senior counsel, said in a statement.

“The vast majority of courts ruling on similar discriminatory laws have struck them down, and the court’s decision here is an outlier that fails to respect the equal dignity of transgender students,” he said.

Idaho Superintendent for Public Instruction Debbie Critchfield, members of the Idaho State Board of Education and members of the Boise School District’s board of trustees are defendants in the case.

Idaho Attorney General Raúl Labrador in a statement called the ruling a significant win for his office.

“Society has separated these intimate facilities for time immemorial, and it is particularly important that the safety and privacy interests of minor students are protected,” Labrador said.

Republican Sen. Ben Adams, of Nampa, sponsored the measure, and the Idaho Family Policy Center, a religious lobbying group, helped write it. The group also pushed a new Idaho law criminalizing gender-affirming health care for minors.

Many GOP-controlled states have passed similar anti-transgender laws.

In August, a federal appeals court upheld a decision blocking Idaho’s 2020 first-in-the-nation ban on transgender athletes in girls and women’s sports.

In that case, a three-judge panel of the 9th U.S. Circuit Court of Appeals ruled that the ban discriminates against 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.