JACKSON, Miss. (AP) — A transgender girl from Mississippi’s Gulf Coast who wanted to wear a dress to a regional band event was discriminated against when her school insisted she follow a dress code based on her sex assigned at birth, according to a new civil rights complaint.

The American Civil Liberties Union and the ACLU of Mississippi want the Harrison County School District to get rid of its sex-based distinctions in the dress code and stop enforcing the rules in a way that discriminates against girls, according to an administrative complaint filed Wednesday with the U.S. Department of Education’s Office for Civil Rights.

The ACLU says the district’s dress code violates Title IX, the 1972 law originally passed to address women’s rights. The law prohibits discrimination on the basis of sex by any educational programs or activities that receive federal money. The district rule that students’ clothing must match their sex assigned at birth was added to the dress code policy relatively recently, in July 2023.