The Democrat-controlled Senate is scheduled to vote Wednesday on the bill. It will then go to the House, where it is also expected to pass.
"Our responsibility as a state is to have laws that ensure the well-being of each of our citizens," said the Rev. Davida Foy Crabtree, minister for the Connecticut Conference of the United Church of Christ.
But opponents said they believe there is still time to scuttle the bill or amend it with language defining marriage as a union between a man and a woman. If the bill passes both chambers, opponents vowed to pressure Republican Gov. M. Jodi Rell to veto it.
Rell has said she supports the concept of civil unions. However, she has not taken a stand on the bill, which extends all rights and privileges of marriage to same-sex couples but without an actual marriage license.
"The legislators have not yet heard from the people. They're not listening," said Brian Brown, executive director of the Family Institute of Connecticut. "Connecticut, we're the ones that are doing something far, far different than the rest of the United States."
Voters in Kansas went to the polls Tuesday to decide whether to approve a constitutional amendment prohibiting gay marriage. If approved, Kansas would become the 18th state with such a prohibition in its constitution.
Alabama, South Dakota and Tennessee plan elections next year on constitutional gay marriage bans, and proposals are pending in 13 other states, according to the National Conference of State Legislatures.
Vermont is the only state that recognizes civil unions, while Massachusetts allows same-sex couples to marry.
By Susan Haigh