Transgender students in South Dakota could be prevented from playing on high-school sports teams based on their gender identity due to a new bill that would force them to compete as the gender assigned to them at birth. Existing statewide policy lets students participate in sports “in a manner consistent with their gender identity,” regardless of the sex listed in their student record or birth certificate. But the proposed legislation would make the gender on a student’s birth certificate the “sole determinant” of their “sexual identity,” CNN reports. Lawmakers claim the bill would make competitions fairer, but civil-rights organizations have strongly criticized the move. “No one is harmed by allowing transgender people to compete consistent with who they are. House Bill 1225 is clearly fueled by a fear and misunderstanding of transgender youth in our state,” said Libby Skarin of the American Civil Liberties Union of South Dakota.