Gay marriage backers in Maryland are looking for four more votes in the Senate to approve a gay marriage bill.

Twenty senators have publicly voiced their support for a bill that would make Maryland the sixth state to extend the right to marry to gay and lesbian couples.

On Thursday, Republican State Senator Allan Kittleman announced he would vote in favor of the bill and drop his plan to introduce a competing measure that would limit government recognition of gay and lesbian couples to civil unions. The Senate's GOP caucus has voted to take an official position against the measure. Such a position requires the backing of a majority of members. Kittleman stepped down of his own accord as Senate minority leader last month in part over his dissenting opinion on marriage equality.

The measure appears to be headed for an easy victory in the House.

Six Democratic senators remain undecided, according to a Washington Post survey. They are Senators John C. Astle, Joan Carter Conway, Ulysses Currie, Edward J. Kasemeyer, Katherine A. Klausmeier and James C. Rosapepe.

On Thursday, Maryland Lt. Gov. Anthony G. Brown came out in support of the measure.