FILE PHOTO: The U.S. Supreme Court building is pictured in Washington, U.S., March 20, 2019. REUTERS/Leah Millis/File Photo

WASHINGTON (Reuters) - The U.S. Supreme Court on Tuesday preserved a Pennsylvania school district’s policy accommodating transgender students, declining to hear a challenge backed by a conservative Christian group to rules letting them use bathrooms matching their gender identity.

The justices left in place a 2018 lower court ruling that upheld the Boyertown Area School District policy, which was challenged by six former or current high school students, though the action does not set a national legal precedent. The Supreme Court scrapped plans to hear a major transgender rights case involving bathroom access in public schools in 2017 and has never issued a decisive ruling on the matter.

The students challenging the policy argued that it violated their right to privacy under the U.S. Constitution’s 14th Amendment and a federal law that prohibits sex discrimination in education, known as Title IX. They were backed by the Alliance Defending Freedom, a conservative Christian legal group that has been involved in several major Supreme Court cases.

The Boyertown schools policy allows certain transgender students on a case-by-case basis to use locker rooms and restrooms that correspond to their gender identity. There is only one high school in the district, Boyertown Area Senior High School, which is located in the outer suburbs of Philadelphia.

Democratic former President Barack Obama’s administration in 2016 issued guidance to American public schools to let transgender students use the bathrooms that correspond to their gender identity, a milestone in the history of transgender rights in the United States. That and other Obama policies supporting transgender rights triggered a backlash from Christian conservatives and some Republican politicians.

Just a month after taking office in 2017, Republican President Donald Trump’s administration rescinded the Obama guidance. The administration has taken other steps to limit transgender rights including a Justice Department conclusion that a federal law against workplace discrimination on the basis of sex does not cover transgender or gay employees.