A bill to introduce gay marriage in Maryland has passed its third and final reading in the Senate on Thursday evening by 25 votes to 21. Although the bill must pass in house of delegates, the state’s governor Martin O’Malley has pledged to sign it.

The Religious Freedom and Civil Marriage Protection Act will remove gender references in the US state’s marriage laws and give churches the right not to conduct ceremonies.

The debate will now continue in the House of Delegates on Friday but it is many expect that they will pass the measure.

But, Keiffer Mitchell, the Democrat sponsor of the legislation warned against complacency: “The Senate has been congenial. The House is going to be a lot more volatile. There are more personalities in the mix. I’m concerned about the tone.”

The bill currently has 58 sponsors in the House of Delegates, but 71 votes are needed for the bill to become law. Some predict that if it is passed, it may be passed to voters to decide on a referendum.

Politicians who oppose the measure will reportedly introduce controversial amendments, such as proposals to allow restaurants and hotels to ban gay couples.

If the bill turns into a law, Maryland will be the sixth US state to offer full marriage equality. The state recognises gay marriages performed in other states.

A Republican senator, Allan Kittleman, has suggested that the state should adopt a civil union bill, similar to the one signed into law by the governor of Hawaii last night.

Yesterday, the White House revealed that president Barack Obama’s administration would not defend a case brought against the government arguing that the Defense of Marriage Act is unfair. The president, through his attorney general said that defining a marriage as being between a man and a woman is unconstitutional. Other groups, in particular Congressional leaders could still defend the legal challenges to the law.