A U.S. appeals court on Wednesday ruled that a Virginia school board acted unlawfully in preventing a transgender student from using a bathroom at his high school that corresponded with his gender identity.

The Richmond, Virginia-based 4th U.S. Circuit Court of Appeals ruled on a 2-1 vote that Gavin Grimm, now a college student, is protected under federal law that bars sex discrimination in education and the U.S. Constitution's requirement that people be treated equally under the law.

Grimm's lawsuit dates back to 2015. Grimm sued the Gloucester County School Board after officials at a local public high school refused to allow him to use the boys' restrooms. Born a girl, Grimm identifies as male.

Judge Henry Floyd, writing for the 4th Circuit, said the school board's actions constituted "a special kind of discrimination against a child that he will no doubt carry with him for life."

The appeals court upheld a federal judge's 2019 ruling in Grimm's favor.

Bathroom access has become a major issue in the battle over transgender rights, and Grimm's suit has been the most prominent legal case on the subject.

Grimm's case was previously set to be argued in 2017 before the U.S. Supreme Court but was taken off the schedule after President Donald Trump's administration rescinded guidance previously issued by the administration of President Barack Obama regarding bathroom access for transgender students.

Wednesday's decision cited the Supreme Court's landmark June ruling that gay and transgender people are protected under a federal law that bars sex discrimination in employment.

Floyd wrote that in light of that ruling, "we have little difficulty in holding that a bathroom policy precluding Grimm from using the boys restrooms discriminated against him."

The 4th Circuit ruling potentially could be appealed to the Supreme Court.

The Trump administration has taken a series of steps to limit the rights of transgender Americans. A federal judge on Aug. 17 blocked a Trump administration rule that would strip protections for transgender people facing healthcare discrimination.