The Trump administration on Friday filed a brief with the Supreme Court arguing that transgender workers are not protected by federal civil rights law.

The brief was submitted in a case concerning Aimee Stephens, a transgender woman who was fired from a Detroit funeral home after she informed her employer that she was beginning her gender transition. The case, R.G. & G.R. Harris Funeral Homes v. Equal Employment Opportunity Commission, et al., is one of three cases concerning LGBTQ workers’ rights that the Supreme Court is expected to hear this fall.

The brief, submitted by Solicitor General Noel J. Francisco and other Department of Justice attorneys, argues that Title VII of the Civil Rights Act of 1964, which prohibits employment discrimination based on race, color, religion, sex and national origin, “does not bar discrimination because of transgender status.”

“In 1964, the ordinary public meaning of ‘sex’ was biological sex. It did not encompass transgender status,” the brief states. “In the particular context of Title VII — legislation originally designed to eliminate employment discrimination against racial and other minorities — it was especially clear that the prohibition on discrimination because of ‘sex’ referred to unequal treatment of men and women in the workplace.”

If the Supreme Court sides with the Trump administration, it will be overturning a decision by the 6th U.S. Circuit Court of Appeals, which sided with Stephens in March 2018.

“Discrimination against employees, either because of their failure to conform to sex stereotypes or their transgender and transitioning status, is illegal under Title VII,” Judge Karen Nelson Moore wrote in the 6th Circuit’s decision. “The unrefuted facts show that the Funeral Home fired Stephens because she refused to abide by her employer’s stereotypical conception of her sex.”