Supporters of California's gay marriage ban, Proposition 8, argue that federal District Court Judge Vaughn Walker should have recused himself because he's gay and in a long-term relationship, the AP reported.

Protect Marriage, the coalition of mostly Christian conservative groups defending the law, have appealed U.S. District Judge James Ware's June ruling against their request to invalidate Walker's August 2010 ruling overturning the 2008 voter-approved law because Walker has since acknowledged that he's gay and in a ten-year relationship with a physician.

The 67-year-old Walker acknowledged his sexual orientation after he ruled on the case and subsequently retired from the bench.

In their filing to the Ninth Circuit Court of Appeals, Protect Marriage insisted the judge should have disclosed any interest he may have had in marrying his partner or disqualified himself.

“Although a judge may choose to avoid disclosure by recusing himself without explanation, he cannot both remain silent and sit in judgment of a case in which a reasonable observer, with knowledge of all of the relevant facts (disclosed or not) would conclude the judge's impartiality might reasonably be questioned,” lawyers for Protect Marriage said in written arguments.

Lawyers arguing against the gay marriage ban, countered that judges should step aside from hearing a case only when they have a “substantial and individualized interest in the case, particularly a financial interest, that gives rise to actual bias.”