The US Department of Education’s Office for Civil Rights ruled Monday that the University of Pennsylvania violated Title IX guarantees against sex discrimination when it allowed a transgender woman to compete on its women’s swimming team.

Penn has maintained that it was in full compliance with all National Collegiate Athletic Association rules and eligibility at the time it allowed Thomas to compete and remains so.

The U.S. Education Department wants Penn to strip swimmer Lia Thomas of awards and apologize to female swimmers. The school has said it followed NCAA and Ivy League policies.