The Trump administration said Monday that the University of Pennsylvania violated Title IX by letting a transgender swimmer compete on the school’s women’s team and enter into women’s facilities. It gave Penn 10 days to voluntarily resolve the violations,

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.

The Trump administration says the University of Pennsylvania illegally denied women equal opportunities by letting a transgender swimmer compete on the school’s women’s team and into team facilities.