The states and advocacy groups filed the lawsuits in federal courts in Alabama, Louisiana and Texas challenging new U.S. Department of Education regulations that extend sex discrimination protections in federal civil rights law to LGBTQ students.

The department said the regulations issued on April 19 clarified that the prohibition against sex-based discrimination in schools and colleges that receive federal funding contained in Title IX of the Education Amendments of 1972 also includes discrimination based on sexual orientation and gender identity.

The department cited a 2020 U.S. Supreme Court decision holding that a ban against sex discrimination in the workplace contained in a different law, Title VII, covered gay and transgender workers.

Courts often rely on interpretations of Title VII when analyzing Title IX as both laws bar discrimination on the basis of sex.

The regulations also change how schools subject to Title IX respond to reports of sex-based discrimination and harassment. Title IX applies to both public and private schools, nearly all of which nationally accept some form of federal funding.

In a lawsuit filed on Monday, Republican Texas Attorney General Ken Paxton said the Supreme Court's decision in Bostock v. Clayton County did not extend beyond Title VII to other federal laws prohibiting sex discrimination.

That lawsuit, along with a separate one filed by Republican state attorneys general in Louisiana, Mississippi, Montana and Idaho, argued the regulations unlawfully interpret Title IX in a way that conflicts with the statute's text, which they said defines "sex" as a person's biological sex.

A third lawsuit, by Alabama, Florida, Georgia, South Carolina and three advocacy groups, challenged that provision as well as parts of the regulations they said broadens the definition of sex-based harassment and required schools to overhaul how they address complaints.

The lawsuit said the new, broader ban against harassment would have the effect of forcing students to use someone's preferred pronouns or face the risk of investigation for misgendering someone.

The states said that unless the regulations are vacated, schools will be required to allow transgender students to use restrooms and locker rooms conforming to their gender identities.

An Education Department spokesperson in a statement said it crafted the rule "to give complete effect to the Title IX statutory guarantee that no person experiences sex discrimination in federally funded education."

Paxton filed his lawsuit in federal court in Amarillo, whose only active judge, U.S. District Judge Matthew Kacsmaryk, is an appointee of Republican former President Donald Trump and former Christian legal activist who often rules against LGBTQ rights.

Kacsmaryk, who gained national attention last year after suspending approval of the abortion pill mifepristone, had in 2022 in a different case concluded the Supreme Court's Bostock ruling had no effect on Title IX's "ordinary public meaning."