A California appeals court has ruled that a voter-approved ban on same-sex marriage is unconstitutional.

The three-member panel issued the ruling Tuesday in San Francisco.

The vote was 2-to-1, with the two judges appointed by Democrats voting to overturn the ban, while the judge appointed by a Republican voted in favor of the ban.

The ban, known as Proposition 8, passed in 2008 with 52 percent of the vote. The vote came just months after the state had approved gay marriages.

Supporters of the ban are expected to appeal Tuesday's decision.

In 2010, a judge declared the ban unconstitutional. But lawyers for supporters of the ban appealed, arguing the judge should have been disqualified or recused himself because his long-term same-sex relationship meant he could have had a personal interest in allowing marriages between homosexual couples.

Several U.S. states and the District of Columbia allow gay couples to marry.