COLUMBIA, South Carolina (AP) – South Carolina’s Republican governor has quietly signed into law a bill that would ban transgender students from playing girls’ or women’s sports in public schools and colleges.

Gov. Henry McMaster’s signature Monday means South Carolina joins about a dozen other states that have passed similar laws requiring transgender students to compete with the biological sex listed on their birth certificates.

McMaster posted on Twitter the day after that he was proud to enact the proposal to protect young men and women.

Opponents of the law say it singles out students who aren’t elite athletes but are just looking for a way to be a regular student.