Here’s a partnership you don’t see every day: The Colorado Springs-based Family Policy Alliance and the liberal activist group the Women’s Liberation Front, known as WoLF, over the restroom choice of transgender people.

The unlikely partners filed a friend-of-the-court brief in a case before the U.S. Supreme Court over the request of a Virginia transgender student to use the boys’ restroom at school in Gloucester School Board v. G.G.

The high court agreed to take the case in October after a lower court ruled in favor of the student, Gavin Grimm. Last summer the Supreme Court issued a temporary stay in the ruling to consider an appeal from the local school board.

The case marks the first time the Supreme Court has taken up the transgender bathroom issue, though it exploded as an issue across the country last year, including, to a lesser extent, Colorado.

The Family Policy Alliance/WoLF brief argues that “allowing males who self-identify as women access to female-only spaces threatens the safety of women and girls and results in the effective erasure of women under Title IX – a civil rights law enacted specifically to benefit women, who have been excluded from and discriminated against in the educational arena for centuries,” the Family Policy Alliance said in a statement.

“How wrong does something need to be for a Christian family group, and a radical feminist group, to take their argument together to the Supreme Court?” said Autumn Leva, director of policy for Family Policy Alliance, the public policy partner of Focus on the Family. “Privacy and safety matter and we’re asking the high court to acknowledge that.”

Kara Dansky, who leads the WoLF Board of Directors, said in a statement: “WoLF fights to protect all women and girls, regardless of political affiliation. WoLF is the only feminist organization standing up for the rights of women and girls. It’s important to understand that this goes far beyond bathrooms. Gender identity ideology presents a threat to women as a legal category worthy of civil rights protections.”

Democrats in the Colorado legislature have used their majority in the House to block bills that would deny such public accommodations to transgender people.

In a committee debate over a locker-room bill in 2015, Rep. Joe Salazar, D-Thornton, a civil rights lawyer, said he saw parallels between segregation of transgender people and the nation’s history of racism in the use of public facilities.

“The reasons for non-desegregating in the 1950s and ’60s was because Mexicans and blacks somehow were sexual perverts,” he said. “I’m offended by this bill, because this is rinse-and-repeat prejudice.”