The father, James Boldt, converted to Judaism in 2004 and wants the boy to be circumcised as part of the faith. The mother, Lia Boldt, appealed to the high court, saying the operation could harm her son physically and psychologically.

The state Supreme Court ruled that earlier court decisions failed to determine whether the boy wanted the circumcision, as his father contended, or opposed it, as his mother alleged.

The Supreme Court sent the case back to the trial court to answer that question.

If the trial court finds the child agrees to be circumcised, the Supreme Court said, it should deny the mother's requests. But if the trial court finds the child opposes the circumcision, the court has to determine if it will affect the father's ability to care for the child.

The custody dispute began when the child was 4 and the circumcision issue began three years ago when he was 9.

James Boldt, a lawyer, is representing himself, had no comment, his office said. The attorney for both sides also declined to comment.

The case has drawn attention from Jewish groups concerned that the Oregon court might restrict the practice. A group called Doctors Opposing Circumcision backs the mother.

The courts have steered clear of religious or medical issues, focusing on the questions of custody and care of the child.

One constitutional law professor who has been following the case called it "a reasonable ruling."

"I think what may be delicate and tricky is ... how much we can trust what the 12-year-old says, given the circumstances," said Carl Tobias of the University of Richmond. "He likely feels some pressure from (his parents)."

More than a million U.S. infants are circumcised each year, but circumcising adults or teens remains relatively rare. A urologist who met with the boy submitted an affidavit that said the procedure would cause him minor discomfort for about three days but not interfere with his normal activities, the Supreme Court's decision said.