Prompted by the Trump administration’s reversal of the federal government’s position on transgender rights, the Supreme Court announced on Monday that it would not decide whether a transgender boy in Virginia could use the boys’ bathroom at his high school.

The decision not to take his case, which came as the court is awaiting the appointment of a ninth member, means there will be no ruling on the highly charged issue of transgender rights this term. The issue will almost certainly return to the Supreme Court, probably in a year or two.

Until then, lawsuits in the lower courts will proceed, the political climate and public opinion may shift, and the court’s composition will almost certainly change.

Monday’s development was a setback for transgender rights advocates, who had hoped the Supreme Court, which established a constitutional right to same-sex marriage two years ago, would aid their cause.

Instead, in a one-sentence order on Monday, the Supreme Court vacated an appeals court decision in favor of the student, Gavin Grimm, and sent the case back for further consideration in light of the new guidance from the administration.

The Supreme Court had agreed in October to hear the case, and the justices were scheduled to hear arguments this month. The case would have been the court’s first encounter with transgender rights, and it would probably have been one of the biggest decisions of a fairly sleepy term.

The question in the Virginia case was whether Mr. Grimm, 17, could use the boys’ bathroom in his southeast Virginia high school. The Obama administration said yes, relying on its interpretation of a federal regulation under a 1972 law, Title IX, that bans discrimination “on the basis of sex” in schools that receive federal money.

The Department of Education said in 2015 that schools “generally must treat transgender students consistent with their gender identity.” Last year, the department went further, saying that schools could lose federal money if they discriminated against transgender students.

Mr. Grimm attends Gloucester High School. For a time, school administrators allowed him to use the boys’ bathroom, but the local school board later adopted a policy that required students to use the bathrooms and locker rooms for their “corresponding biological genders.” The board added that “students with gender identity issues” would be allowed to use private bathrooms.

The American Civil Liberties Union, which represents Mr. Grimm, told the justices that requiring Mr. Grimm to use a private bathroom had been humiliating and had, quoting him, “turned him into ‘a public spectacle’ before the entire community, ‘like a walking freak show.’”

Full story at The New York Times.