An Ohio state board has advised that judges who perform civil marriages may not refuse to marry gay and lesbian couples.

The opinion from the Ohio Supreme Court's Board of Professional Conduct was issued Friday but announced Monday, according to the Cleveland Plain Dealer.

Toledo Municipal Judge C. Allen McConnell turned to the state's highest court after he refused to marry a lesbian couple in July, saying that it violated his Christian beliefs. The Ohio Supreme Court handles advisory opinions through the professional conduct board.

(Related: Ohio judge refused to marry lesbian couple.)

The board also said that judges may not decide to stop marrying couples in an effort to avoid ceremonies involving gay couples.

“The oath represents the judge's solemn and personal vow that he or she will impartially perform all duties incumbent on the office and do so without regard to the status or class of persons or parties who come before the court,” the board stated in its opinion. “The oath is a reflection of the self-evident principle that the personal, moral and religious beliefs of a judicial officer should never factor into the performance of any judicial duty.”

The board added that a judge who refused to marry gay couples might be viewed as being biased against the LGBT community.

“A judge's decision to decline to perform some or all marriage ceremonies, when grounded on the judge's personal beliefs, may reflect adversely on perceptions regarding the judge's performance of other judicial duties. A judge may reasonably be perceived as having a personal bias or prejudice based on sexual orientation if he or she elects to perform opposite-sex marriages, but declines to perform same-sex marriages.”

A widower fighting to have Ohio recognize his marriage to another man was the lead plaintiff in the Supreme Court case that in June struck down gay marriage bans in all 50 states.