Maine’s highest court ruled last week that school officials violated state anti-discrimination law when they required a transgender fifth-grader to use a staff, rather than a student, restroom. The decision marks the first time a state court has ruled that students must be allowed to use restrooms of the gender with which they identify. Federal courts have not yet ruled on the issue.

The lawsuit, Doe v. Clenchy, arose in 2009 after officials at an Orono, Maine, elementary school denied Nicole Maines, a transgender girl who was in fifth grade at the time, continued use of the girls’ restroom. Officials had previously allowed Maines to use the girls’ restroom until the grandfather of a fifth-grade boy complained to school officials. Following the complaint, the school district determined Maines should use a staff bathroom. Maines, her family, and the state’s Human Rights Commission sued, arguing the action violated Maine’s Human Rights Act, which prohibits discrimination against transgender people.

Last week, the Maine Supreme Court agreed, in a 5-1 decision that reconciled two separate state laws that school officials had argued made it unclear how to comply in situations like Maines’. One law makes it a violation of the state’s Human Rights Act to discriminate in providing access to school bathrooms based on sexual orientation, while another requires schools to provide children with “clean toilets” separated by gender.

According to the court, while school officials are required to provide separate bathrooms for each sex, schools cannot dictate the use of those facilities in a way that discriminates against students in violation of the Maine Human Rights Act. In this case, school officials had worked with Maines and her family, determining she should have access to the girls’ bathroom. In that regard, the school had actually complied with a state anti-discrimination law. But, it was the school’s later decision to ban Maines from the girls’ bathroom that amounted to discrimination on the basis of her sexual orientation, the court found. The school violated the law, the court held, because its decision was in response to complaints by others and not a change in her status as a transgender girl.

Equality advocates celebrated the historic decision that had been years in the making. “This is a momentous decision that marks a huge breakthrough for transgender young people,” said Jennifer Levi, director of GLAD’s Transgender Rights Project, in a statement. “Schools have a responsibility to create a learning environment that meets and balances the needs of all kids and allows every student to succeed. For transgender students this includes access to all school facilities, programs, and extracurricular activities in a way that is consistent with their gender identity.”

“As parents all we’ve ever wanted is for Nicole and her brother Jonas to get a good education and to be treated just like their classmates, and that didn’t happen for Nicole,” said Wayne Maines, Nicole’s father, in a statement following the decision. “What happened to my daughter was extremely painful for her and our whole family, but we can now close this very difficult chapter in our lives. We are very happy knowing that because of this ruling, no other transgender child in Maine will have to endure what Nicole experienced.”

While the court ruled school officials had discriminated in Maines’ case, it clarified that its decision should be construed carefully. Maines had been diagnosed with gender dysphoria when she was preparing to enter fifth grade, a fact the court noted in clarifying the scope of its ruling:

[W]e do not suggest that any person could demand access to any school facility or program based solely on a self-declaration of gender identity or conclusion with the plans developed in cooperation with the school and the accepted and respected diagnosis that are present in this case.

“Our opinion must not be read to require schools to permit students casual access to any bathroom of their choice,” the court wrote. “Decisions about how to address students’ legitimate gender identity issues are not to be taken lightly.”