The lawsuit filed Tuesday in a North Texas federal court seeks to block parts of a nondiscrimination mandate of President Barack Obama's health care law. Republican state officials say the rules could force doctors to help with gender transition against their medical judgment or religious convictions.
Transgender rights advocates called that a far-fetched hypothetical and say the rules simply require doctors to make decisions without bias.
The lawsuit was filed a day after a federal judge in Texas blocked a directive that would have required U.S. public schools to let transgender students use bathrooms consistent with their gender identity.
Wisconsin, Kentucky, Nebraska and Kansas also joined the latest lawsuit.
