A federal appeals court in California has ruled that the state's ban on same-gender marriages is unconstitutional.
Voters in California approved the ban, known as Proposition 8, by a slim majority in November 2008 after a court overturned a law that said only a man and a woman can be legally married.
The case is now likely to end up before the Supreme Court, whose ruling will affect laws in all 50 states.
Same-sex marriage is currently only legal in seven states and Washington, D.C.
A handful of states plan to let voters decide the issue in November.