A North Carolina charter school's requirement that girls wear skirts based on the view that they are "fragile vessels" deserving of "gentle" treatment by boys is unconstitutional, a federal appeals court ruled on Tuesday.

The Richmond, Virginia-based 4th U.S. Circuit Court of Appeals on a 10-6 vote DailyDocket https://tmsnrt.rs/3xPuVWQ sided with three female students who argued Charter Day School's requirement amounted to sex-based discrimination rooted in gender stereotypes that violated their equal protection rights.

The Brunswick County school emphasizes "traditional values" and implemented a dress code that its founder, businessman Baker Mitchell, said in an email and testimony would "preserve chivalry" and ensure girls are treated "courteously and more gently than boys."

The state-chartered school argued the Equal Protection Clause of the U.S. Constitution's 14th Amendment did not apply to it because it was a private entity, not a "state actor."

But U.S. Circuit Judge Barbara Milano Keenan said it was one since North Carolina delegated to it its duty to provide free, universal education to students. A contrary ruling would mean North Carolina could ignore "blatant" discrimination, she said.

"Courts may not subjugate the constitutional rights of these public-school children to the facade of school choice," wrote Keenan, who was joined by her fellow Democratic appointees.

The court also revived a claim brought under Title IX, a federal law that prohibits sex discrimination in federally-funded education.

Galen Sherwin, the students' lawyer at the American Civil Liberties Union, said the ruling "should put charter schools across the country on notice."

The school's lawyer did not respond to requests for comment.

The six dissenting votes were all from Republican-appointed judges, including U.S. Circuit Judge A. Marvin Quattlebaum Jr, who said the decision would stifle "innovative alternatives to traditional public education."

U.S. Circuit Judge J. Harvie Wilkinson called the ruling a "shame" and the school's "chivalric approach should neither be legally banished from the educational system, nor should it be legally imposed."