DES MOINES, Iowa — Iowa lawmakers became the first in the nation to approve legislation removing gender identity protections from the state’s civil rights code Thursday, despite massive protests by opponents who say it could expose transgender people to discrimination in numerous areas of life.

The measure raced through the legislative process after first being introduced last week. The state Senate was first to approve the bill on Thursday, on party lines, followed by the House less than an hour later. Five House Republicans joined all Democrats in voting against it.

The bill would remove gender identity as a protected class from the state’s civil rights law and explicitly define female and male, as well as gender, which would be considered a synonym for sex and “shall not be considered a synonym or shorthand expression for gender identity, experienced gender, gender expression, or gender role.”

The measure would be the first legislative action in the U.S. to remove nondiscrimination protections based on gender identity, said Logan Casey, director of policy research at the Movement Advancement Project, an LGBTQ+ rights think tank.

The bill now goes to Republican Gov. Kim Reynolds, who signed earlier policies banning sports participation and public bathroom access for transgender students. A spokesperson for Reynolds declined to comment on whether she would sign the bill. If she does, it will go into effect on July 1.