A federal appellate court voted Tuesday to block a West Virginia law prohibiting transgender girls from joining girls' sports teams at school, according to the Associated Press .

The 4th U.S. Circuit Court of Appeals voted 2-1 to overturn the legislation signed into law in 2021 by Gov. Jim Justice.

The court ruled that the law violated Title IX , which prohibits discrimination "on the basis of sex" in educational activities programs that receive federal funds.

The 2021 law stated that it was necessary to classify teams by "biological sex," rather than "gender identity," in order "to promote equal athletic opportunities for the female sex."

The lawsuit concerned middle-schooler Becky Pepper-Jackson, a transgender girl who wanted to join her school's girls' cross-country team, according to ACLU West Virginia .

Circuit judge Toby Heytens wrote in the ruling that the the 2021 legislation could not be lawfully applied to Pepper-Jackson, whom he described as "a 13-year-old transgender girl who takes puberty blocking medication and has publicly identified as a girl since the third grade."

If playing on boys' teams, Pepper-Jackson would be playing with athletes "larger, stronger and faster than her," Heytens wrote.

Allowing the West Virginia law to stand would therefore expose Pepper-Jackson "to the very harms Title IX is meant to prevent," Heytens concluded.

The decision overturns an earlier district court ruling against Pepper-Jackson, which had been put on hold by the appellate court.

The ruling is the latest in a series of controversies over state laws seeking to regulate how transgender student-athletes can participate in school sports.

At least 23 additional states have passed laws limiting transgender girls from competing in girls' competitions, according to the Associated Press.

An additional ban is set to go into effect in Ohio in late April, while three more have been blocked by courts in Arizona, Idaho and Utah, the AP reported.

With appellate courts so far split on these challenges, the Supreme Court could eventually weigh in on the issue. Justice Samuel Alito said last year that the West Virginia case "concerns an important issue that this Court is likely to be required to address in the near future."