California state senators could vote today on a bill that makes same-sex marriage legal in the Golden State.

If approved, it would be the first time a state legislative body in the U.S. has voted to OK homosexual matrimony.

AB 849 deletes the phrase "a man and a woman" from California's marriage laws and replaces it with "two persons."

If it wins passage – and the vote is expected to be very close – the bill would then go to the state Assembly and ultimately to Gov. Arnold Schwarzenegger.

The Campaign for Children and Families urged supporters in an e-mail to contact their legislators and ask them to oppose the legislation.

"This would violate Proposition 22, which California voters passed to say marriage is only for a man and a woman," said a statement from the group.

The bill needs 21 votes in the 40-member state Senate to pass.

"It'll be a close vote, but I think we'll have a victory," Equality California Executive Director Geoffrey Kors told the Bay Area's Daily Review.

The bill fell short of passage in the Assembly in June, but supporters believe if it passes first in the Senate, Assembly members will be more apt to approve it.

If the Senate passes it, the Assembly will have until Sept. 9 to act on the bill.

"We think we're making progress in the Assembly and have a realistic chance," Kors told the paper.

The bill is sponsored by Assemblyman Mark Leno, D-San Francisco.

Meanwhile, same-sex opponents in the state are hoping to put on the ballot for California voters a constitutional amendment that would go further than Proposition 22 did.

The Voters' Right to Protect Marriage Initiative, according to its website, "protects everything about marriage – marriage licenses, marriage rights, and marriage under law – for one man and one woman. It's the true-blue standard we must unite under to truly protect marriage."

Related stories:

California Dems endorse same-sex civil unions

Same-sex marriage bill advances in California

Federal Marriage Amendment dead?

How homosexual activists took America by surprise

California high court blocks S.F. 'marriages'

Bush announces support for marriage amendment

Activists respond to Bush amendment stance

Marriage defenders slow same-sex tide

Mayor facing charges for same-sex weddings

Another city backs same-sex marriage

Arnold: Terminate same-sex marriage