(CNN) -- A federal judge who ruled against a ban on same-sex marriage in California and later revealed that he is gay showed no evidence he was prejudiced in the case, according to a ruling Tuesday.

U.S. District Court Judge James Ware upheld former colleague's Judge Vaughn Walker's ruling on California's Proposition 8. Questions had been raised about Walker's ability to impartially decide the controversial question of same-sex marriage.

"It is not reasonable to presume that a judge is incapable of making an impartial decision about the constitutionality of a law, solely because, as a citizen, the judge could be affected by the proceedings," Ware ruled.

Ware, based in San Francisco, backed the original ruling by Walker that the voter-approved ban on same-sex marriage in the state was unconstitutional. The new order keeps the issue on track to an expected Supreme Court challenge, perhaps by next year.

On April 6, several weeks after retiring, Walker ended months of speculation by publicly disclosing "that he is gay and that he has been in a committed relationship for more than 10 years," according to a motion filed by Proposition 8 backers, who said they would appeal Ware's ruling.

The previous August, Walker ruled that Proposition 8 violated the Constitution's equal protection clause.

"Proposition 8 does nothing more than enshrine in the California Constitution the notion that opposite-sex couples are superior to same-sex couples," Walker wrote in his 136-page opinion.

The motion said Walker should have either recused himself from the case or disclosed his sexual orientation "so that the parties could consider and decide, before the case proceeded further, whether to request his recusal."

Walker told reporters in April he didn't think it was appropriate for any judge's sexual orientation, ethnicity, national origin or gender to stop them from presiding over a case, according to a Reuters report.

The motion argued that if Walker and his partner ever wanted -- or thought they might want -- to marry, he "plainly had an 'interest that could be substantially affected by the outcome of the proceeding,' " it said, citing federal law regarding disqualification of judges.

"Only if Chief Judge Walker had unequivocally disavowed any interest in marrying his partner could the parties and the public be confident that he did not have a direct personal interest in the outcome of the case," the motion said.

Same-sex marriage advocates decried the motion.

"Supporters of Proposition 8 are grasping at straws because they don't like the outcome," Michael Cole-Schwartz of the Human Rights Campaign said in April. "If their real intent was to 'protect marriage,' they should argue that a straight, married judge be disqualified since he would conceivably have an interest in protecting his own marriage. The argument is simply ridiculous on its face."

Judge Ware wrote that the presumption that "all people in same-sex relationships think alike" is unreasonable.

"The presumption that Judge Walker, by virtue of being in a same-sex relationship, had a desire to be married that rendered him incapable of making an impartial decision, is as warrantless as the presumption that a female judge is incapable of being impartial in a case in which women seek legal relief," Ware said. "On the contrary: it is reasonable to presume that a female judge or a judge in a same-sex relationship is capable of rising above any personal predisposition and deciding such a case on the merits."

Equality California, which argues for civil rights protection, hailed the ruling, saying it "reaches far beyond the LGBT community and is a cause for elation."

Protectmarriage.com said it disagreed with Ware's decision.

"Our legal team will appeal that decision and continue our tireless efforts to defend the will of the people of California to preserve marriage as the union of a man and a woman," attorney Charles J. Cooper said.

In New York, meanwhile, Gov. Andrew Cuomo proposed a bill Tuesday that would legalize same-sex marriage, effectively delivering on a promise he has made since taking office in January.

The Marriage Equality Act would grant same-sex couples equal rights to marry "as well as hundreds of rights, benefits and protections that are currently limited to married couples of the opposite sex," according to a news release from Cuomo's office.

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CNN's Ashley Hayes and Augie Martin contributed to this report.