The Lebanon High School senior's attorney from the American Civil Liberties Union of Indiana said in court filings that the girl, a lesbian, does not wear dresses because she feels they indicate a sexual identity that is not her own, the Indianapolis Star reported Thursday.
The girl, who was not identified by name in the lawsuit, is asking a federal court to force the school to allow her to wear the same attire as male students, said ACLU of Indiana Legal Director Ken Falk.
"From a First Amendment standpoint, wearing a tuxedo makes an affirmative statement about her own sexuality," Falk said in a filing. "Students have free-speech rights."
Falk said the district's policy of only letting boys wear tuxedos to a prom is also a violation of the federal Title IX law, which band schools from discriminating along gender lines.
Kent Frandsen, an attorney for the Lebanon School District, said officials are investigating whether they have a legal obligation to allow the girl to wear a tuxedo to the April 25 prom.