LITTLE ROCK, Ark. (AP) — Seven more Republican-led states sued Tuesday to challenge a new federal regulation that seeks to protect the rights of transgender students in the nation’s schools. Republican plaintiffs call the effort to fold protection for transgender students under the 1972 Title IX law unconstitutional.

The lawsuits filed in federal courts in Missouri and Oklahoma are the latest GOP attempts to halt the new regulation seeking to clarify Title IX, a landmark 1972 sex discrimination law originally passed to address women’s rights and applied to schools and colleges receiving federal money. The rules spell out that Title IX bars discrimination based on sexual orientation and gender identity, too.

Arkansas, Iowa, Nebraska, North Dakota and South Dakota joined as plaintiffs in the Missouri lawsuit.

The cases come as many Republicans seek to limit the rights of transgender youth, including restricting which bathrooms or pronouns they can use in school. Such prohibitions that could be invalidated by the new federal regulation. The GOP states suing argue that the new federal rules goes beyond the intent of Title IX and that the Biden administration doesn’t have the authority to implement them.