Courtesy Jeff Belmonte/Creative Commons

Washington became the seventh state to legalize same-sex marriage, when Gov. Christine Gregoire on Monday signed a bill allowing gay and lesbian couples to wed.

Those weddings can begin on June 7, the day the new law takes effect.

But opponents to same-sex marriage are already planning initiatives to overturn the new law, the Associated Press reported.

Gregoire signed the bill into law one week after a federal appeals court struck down California's Proposition 8, a voter-approved initiative banning same sex marriage. The court ruled that the measure was unconstitutional.

Same-sex marriages are already legal in New York, Connecticut, Iowa, Massachusetts, New Hampshire, Vermont and the District of Columbia.

Also on Monday, the New Jersey state Senate passed a bill legalizing such marriages. The New Jersey Assembly will vote on the measure later this week, but the state's governor, Chris Christie, has vowed to veto it.

Christie wants voters to weigh in on the issue, according to the AP.