RICHMOND, Va. – A federal appeals court is set to hear arguments in a long-running legal challenge by a transgender man who sued a Virginia school board after he was barred as a student from using the boys' bathrooms at his high school.

A judge ruled last year that the Gloucester County School Board discriminated against Gavin Grimm. The school board has appealed that ruling to the 4th U.S. Circuit Court of Appeals in Richmond. The court will hear arguments Tuesday.

The American Civil Liberties Union argues that the school board violated Grimm's rights under the U.S. Constitution's equal protection clause as well as under Title IX, the federal policy that protects against gender-based discrimination.

Attorneys for the school board have argued that the lower court judge wrongly interpreted federal protections. The board says the law protects against discrimination based on gender, not gender identity.

Grimm was born a female but transitioned to male. The board argues that Grimm is still physically female and was treated like all other students when he was required to use girls' restrooms or a private bathroom.

Grimm’s lawsuit was once a federal test case that drew national attention. He graduated from high school in 2017.