The lawsuit was filed in February by three female high-school school students and their families against the Connecticut Interscholastic Athletic Conference, which since 2017 has permitted male students who identify as females to participate in women’s sports programs.

“Under CIAC’s interpretation of Title IX…schools may not account for the real physiological differences between men and women. Instead, schools must have certain biological males — namely, those who publicly identify as female — compete against biological females,” Barr and other Justice Department officials wrote in the statement of interest. “In so doing, CIAC deprives those women of the single-sex athletic competitions that are one of the marquee accomplishments of Title IX.”

Lawyers for the students argue that the inclusion of biological males in women’s sports constitutes a breach of Title IX rules preventing discrimination based on sex in federally-funded programs.

“Males will always have inherent physical advantages over comparably talented and trained girls — that’s the reason we have girls sports in the first place,” Christina Holcomb, one of the lawyers representing the students from the non-profit Alliance Defending Freedom, told reporters on Wednesday. “A male’s belief about his gender doesn’t eliminate those advantages.”

After the students filed their lawsuit in Connecticut, the Arizona state House passed a bill banning the participation of transgender females in women’s sports programs. Backers of the law cited the Connecticut lawsuit in support of the measure.