A federal judge in California has upheld a ruling that declared Proposition 8, California's gay marriage ban, unconstitutional.

Proponents of the ban on Monday asked U.S. District Judge James Ware to invalidate Judge Vaughn Walker's August ruling overturning the 2008 voter-approved ban because Walker has since acknowledged that he's gay and in a ten-year relationship with a physician.

The 67-year-old Walker acknowledged that he's gay after he retired from the bench.

Lawyers for Protect Marriage, the coalition of socially conservative groups defending the law, argued that Walker should have recused himself because he's in a same-sex relationship and stood to personally benefit from the verdict.

“It now appears that Judge Walker, at the time the complaint was filed and throughout this litigation, occupied precisely those same shoes as the plaintiffs,” attorney Charles Cooper said.

Lawyers representing the two gay couples challenging the constitutionality of the law called the motion a thinly veiled attack on Walker's sexual orientation.

Ware said on Tuesday that Walker's sexual orientation did not create a conflict of interest.

Ware “erased all doubt that the Prop 8 trial was anything but fair and thorough and sent a powerful message that extreme fringe groups cannot strong-arm the law,” said Chad Griffin, board president of the American Foundation for Equal Rights (AFER), the group formed specifically to challenge the law.

“Prop 8 is hanging by a thread,” he added.

The U.S. 9th Circuit Court of Appeals put Walker's ruling on hold as it considers an appeal.