The U.S. Supreme Court on Monday refused to hear a challenge to an Oregon school district's bathroom policy for transgender students, leaving in place a lower court's order upholding the policy that allows transgender students to use the bathroom of their choice.

Without explanation, the high court rejected an appeal to the case.

Parents in the small city of Dallas, Oregon sued over the policy in 2017, claiming that it created a “hostile educational environment.”

“The district's directive interferes with the parents' rights to direct the upbringing of their children, schoolchildren's rights to bodily privacy, parents' and children's right to free exercise of religion, and children's rights to be free from hostile educational environments under Title IX [of the Education Amendments of 1972],” they said in their petition.

Plaintiffs in the case, Parents for Privacy and Parents Rights in Education, claim that such policies violate the rights of non-transgender students.

The Ninth Circuit Court of Appeals in San Francisco sided with the district's policy of allowing transgender students to use the bathrooms and locker rooms that they identify with.

The American Civil Liberties Union (ACLU) and the ACLU of Oregon intervened in the case on behalf of Basic Rights Oregon, a local LGBT rights advocate.

Gabriel Arkles, senior staff attorney at the ACLU's LGBT and HIV Project, said in a statement that the high court “did the right thing.”

“There is just no legal basis for what the other side wants: mandated discrimination against trans students,” Arkles said. “In a time when we see attacks on trans youth around the country, from here in Oregon to Connecticut and South Dakota, it's more important than ever to work together to defend our communities.”

The Trump administration repealed Obama-era guidance allowing transgender students to use the bathrooms and locker rooms of their choice.