Gay marriage opponents fight ruling
Opponents of gay marriage are appealing against a federal judge's decision to overturn a ban in California.
The appeal to the 9th US Circuit Court of Appeals was expected, as lawyers on both sides of the legal battle repeatedly vowed to carry the fight to a higher court if they lost.
On Wednesday, a federal judge in San Francisco overturned California's Proposition 8, which restricts a marriage to one man and one woman.
US District Court Judge Vaughn Walker ruled the law violates federal equal protections and due process laws.
The 9th Circuit court has no deadlines to hear the case, which will be randomly assigned to a three-judge panel.
It is expected that the panel will order both sides to submit written legal arguments before scheduling a hearing.
The outcome in the appeals court could force the US Supreme Court to confront the question of whether gays have a constitutional right to wed.
"This ruling, if allowed to stand, threatens not only Prop 8 in California but the laws in 45 other states that define marriage as one man and one woman," said Brian Brown, president of the National Organisation for Marriage, which helped fund the 2008 campaign that led to the ban's passage.
Currently, same-sex couples can legally wed only in Massachusetts, Iowa, Connecticut, Vermont, New Hampshire and Washington, DC.
Protect Marriage, the coalition of religious and conservative groups that sponsored Proposition 8 - and wound up defending it in court after California Governor Arnold Schwarzenegger and Attorney General Jerry Brown refused to - said it would immediately appeal against the judge's decision.