Maryland state senators have voted to allow same-sex marriage, sending the bill on to the House of Delegates for approval.

One Republican, Sen. Allan Kittleman of Howard, joined 24 Democrats to pass the bill with 21 opposing. A majority of 24 of 47 senators was needed.

If the House passes the measure and the governor signs it, Maryland would become the sixth state in the union to legalize gay marriage.

Opponents, including Senate President Thomas V. Mike Miller, D-Calvert, vowed to keep up the fight should it become law. The issue would be put on the 2012 ballot for voters to have a final say, he said.