Iowa’s Republican-controlled legislature passed a bill on Thursday to remove gender identity as a protected class from the state civil rights law, which currently equates sex discrimination to discrimination based on gender identity.

The measure sped through the legislature after lawmakers introduced it last week. The Iowa senate approved the bill less than an hour before the Iowa house did the same. The bill now heads to Governor Kim Reynolds’s desk for approval, despite the presence of thousands of protesters at the Iowa state capitol before the votes.

A large mob of LGBT activists descended on the state legislature in Des Moines, holding Pride flags and signs supporting transgender rights and opposing the legislation. More than 2,500 people protesting the bill entered the government building on Thursday, the Des Moines Register reported. State troopers were stationed around the rotunda to prevent any physical unrest.

The bill, if signed into law, would strip gender identity from the Iowa Civil Rights Act of 1965, which prohibits discrimination based on race, color, creed, sex, sexual orientation, religion, national origin, or disability.

In 2007, sexual orientation and gender identity were added to the state’s civil rights code by Democrats who controlled the legislature and governor’s office at the time.

Additionally, the legislation would require birth certificates to state an Iowa resident’s biological sex as either male or female and explicitly define sex to mean “the state of being either male or female as observed or clinically verified at birth.”

It would also define gender as a synonym for sex. Gender, according to the text, “shall not be considered a synonym or shorthand expression for gender identity, experienced gender, gender expression, or gender role.”

In a previous case, the Iowa supreme court rejected the plaintiff’s argument that sex discrimination covers gender identity as a protected class.

“Discrimination based on an individual’s gender identity does not equate to discrimination based on the individual’s male or female anatomical characteristics at the time of birth (the definition of ‘sex’),” the court said. “An employer could discriminate against transgender individuals without even knowing the sex of the individuals adversely affected.”

The bill adds to the state’s bans on male athletes participating in women’s sports and entering intimate female spaces, such as bathrooms and locker rooms. Reynolds signed those policies into law, as well as a measure banning transgender procedures and treatments for minors.

The law’s provisions are similar to President Donald Trump’s executive order that formally recognizes two sexes, male and female. Unlike the previous administration’s policies, Trump’s order does not recognize the concept of gender identity.

Like Iowa, several Republican-led states are moving to enact laws that create legal definitions for biological sex following the executive order. Wyoming, Arizona, Indiana, Missouri, and South Carolina are some states considering binary sex bills. In Alabama, Governor Kay Ivey signed one into law earlier this month. Meanwhile, Kansas passed such a law in 2023 before Trump returned to office.