Proponents of California's gay marriage ban said a judge who struck down the law was biased because he is in a same-sex relationship himself, and his ruling should be thrown out.

Former Judge Vaughn Walker last year ruled that California's same-sex marriage ban, known as Proposition 8, was unconstitutional.

The case is being appealed and is expected to be pursued to the US Supreme Court, potentially setting national precedent.

Proponents said Walker's 10-year relationship, which he disclosed after stepping down from the bench this year, should have led him to avoid the case.