Nebraska Gov. Jim Pillen signed an executive order Wednesday narrowly defining a person’s sex, a move that LGBTQ rights advocates have said will write transgender and gender-nonconforming people out of state law.

The executive order signed Wednesday by Pillen legally defines females as individuals “whose biological reproductive system is designed to produce ova” and males as individuals “whose biological reproductive system is developed to fertilize the ova of a female.” It charges state agencies to define a person’s sex as that with which they were assigned at birth.

Pillen in Wednesday’s order wrote that biological differences between cisgender males and females are “immutable” and “enduring” and “there are legitimate reasons to distinguish between the sexes” in areas where “biology, safety, and/or privacy are implicated.”

“It is common sense that men do not belong in women’s only spaces,” Pillen said Wednesday in a statement. “As Governor, it is my duty to protect our kids and women’s athletics, which means providing single-sex spaces for women’s sports, bathrooms, and changing rooms.”

The order, which went into effect immediately, will expire if Nebraska lawmakers pass legislation that bars transgender women and girls from competing on female school sports teams and prevents transgender people from using facilities that are consistent with their gender identity.

A bill to restrict transgender participation in school sports and limit access to restrooms and locker rooms was introduced this year by Republican state Sen. Kathleen Kauth. It failed to advance out of committee before the end of a chaotic legislative session marked by a months-long filibuster led by Democrats over another bill to ban gender-affirming health care for transgender minors.

That bill, also sponsored by Kauth, sought to prevent health care providers in Nebraska from administering puberty blockers, hormones and surgeries to transgender children and adolescents younger than 19. It passed after Republicans in the state’s unicameral Legislature combined the bill with another measure to ban abortion after 12 weeks of pregnancy.

Pillen signed the law in May, calling it “the most significant win for social conservative agenda in over a generation of Nebraska” during a signing ceremony in Lincoln. The law, which is scheduled to take effect Oct. 1, is currently being challenged by the American Civil Liberties Union.

In a post on X – the platform formerly known as Twitter – late Wednesday, state Sen. Megan Hunt, a Democrat who led this session’s filibuster with state Sen. Machaela Cavanaugh , criticized Pillen’s executive order, which was signed the same day the University of Nebraska’s volleyball team set a world record for women’s sports attendance.

“Unfortunately, the Governor took advantage of this historic day in which many Nebraskans are gathered together to celebrate and honor women’s athletics, and chose to divide us,” Hunt, who has a transgender child, wrote Wednesday. “The truth is, no executive order can erase trans people. They have always existed and always will.”

Laws narrowly defining a person’s sex were passed this year by Republicans in states including Montana, Kansas and Tennessee. They have been denounced by LGBTQ civil rights groups as attempts to block legal recognition of a transgender person’s gender identity. Oklahoma’s Republican Gov. Kevin Stitt signed an executive order almost identical to Pillen’s earlier this month.