Ten more states sued the federal government Friday over rules allowing transgender kids to use bathrooms corresponding with their gender identity—rather than the sex listed on their birth certificates—in public schools. They join a group of 13 other states already suing the Obama administration over the same mandate. A May 13 directive from the Department of Education and the Department of Justice, which does not carry the force of law, said schools that forced transgender kids to use bathrooms matching their birth sex would be violating Title IX and could lose federal funding. The lawsuit filed Friday is being brought by the states of Nebraska, Arkansas, Kansas, Michigan, Montana, North Dakota, Ohio, South Carolina, South Dakota, and Wyoming.