A transgender student in Mississippi skipped graduation Saturday after a judge backed the school system’s sex-based dress code for the ceremony, according to the student’s legal team.

The American Civil Liberties Union sued the Harrison County School District on behalf of the student — a biological male who identifies as a female — so the 17-year-old could wear women’s clothing to graduation.

A federal judge sided with the school district’s requirement for graduating boys to wear “socks, dress shoes, pants, a button-down shirt and tie” in his Friday ruling.

“The loss of an opportunity to participate in a graduation ceremony is not an unconstitutional infringement on a student’s right to freely exercise his religious beliefs,” U.S. District Judge Taylor McNeel wrote in his ruling, referring to the student with male pronouns.

The teen, who was only identified as L.B. in court documents, decided to skip out on Harrison Central High School’s graduation ceremony held Saturday in response to the ruling.

“Our client is being shamed and humiliated for explicitly discriminatory reasons, and her family is being denied a once-in-a-lifetime milestone in their daughter’s life,” Linda Morris, a staff attorney for the ACLU, told The Associated Press. “No one should be forced to miss their graduation because of their gender.”

The student was said to have worn dresses to class as well as to prom last year. The lawsuit also said that Superintendent Mitchell King told L.B.’s mother that the student had to dress “like a boy” if they were going to be part of the ceremony.

The student did meet the qualifications to receive a high school diploma, an attorney for the school district said.

— This story is based in part on wire service reports.

• Matt Delaney can be reached at mdelaney@washingtontimes.com.