The sponsors of California’s controversial gay marriage ban attempted to disqualify the decision of a federal judge, Vaughn Walker, because he didn’t declare that he was gay when he overturned the state’s gay marriage ban last year.

Judge Walker’s decision is currently the subject of an appeal. But yesterday, a coalition of anti-gay groups told the 9th US Circuit Court of Appeals that Judge Walker should have told the court that he was in a long-term same sex relationship before he presided over the trial on the measure’s constitutionality. The groups claim that he would have benefited from his judgement.

“In May 2009, when Judge Walker read the allegations of the complaint, he knew something the litigants and the public did not know: He knew that he, too, like the plaintiffs, was a gay resident of California who was involved in a long-term, serious relationship with an individual of the same sex,” Charles Cooper who represented the anti-gay groups said. “The litigants did not have any knowledge of these facts, and it appears that Judge Walker made the deliberate decision not to disclose these facts.”

But Judge R Randy Smith, who represents Idaho on in the 9th District Circuit interrupted to ask why a gay judge should be obliged to reveal his sexuality. He asked: “So a married judge could never hear a divorce?”

Mr Cooper replied: “Your honour, I don’t see the difficulty with a married judge hearing a divorce action.”

Judge Smith replied: “Would he have to disclose, ‘Oh, I’ve been married, and we’ve been married for 24 years and we have a relationship that’s kind of difficult’? That’s what you are arguing here?”

Mr Cooper replied that because Judge Walker has come out and revealed he is in a long term relationship, he stood to benefit in the same way as the plaintiffs.

But David Boies, representing two gay couples who successfully sued to strike down Proposition 8 in Judge Walker’s court, attacked the gay rights opponents’ reasoning. He argued that judicial ethics did not force a black judge from bowing out of civil rights cases. He said that it was a “perverse logic that only judges, gay or straight, who have no interest in marrying and the institution of marriage would be the only ones who could hear this case.”