Lawmakers in Colorado on Tuesday approved a bill to allow same-sex civil unions, the latest US state to back legalized gay marriages or partnerships.
Homosexual activists hailed the 39-26 vote by the state's House of Representatives supporting the bill, which has already passed the senate and is expected to come into force on May 1 after Governor John Hickenlooper signs it.
"Congratulations, Colorado," said Rea Carey, head of the National Gay and Lesbian Task Force, adding that "while not a substitute for full civil marriage, this measure is an important step forward.
"This is about love and fairness, pure and simple. Same-sex couples and our families simply want to be treated fairly, as our friends, neighbors and co-workers already are," she added.
"We want to be able to provide for and protect our families, just as everyone else does. This measure helps make this more possible for all the loving, committed same-sex couples and families throughout Colorado."
There are currently nine US states plus the District of Columbia which allow full same-sex marriage: Maryland, Maine, Washington, Connecticut, Iowa, Massachusetts, New Hampshire, Vermont and New York, plus the national capital.
Colorado joins eight other states -- California, Delaware, Hawaii, Illinois, Nevada, New Jersey, Oregon, and Rhode Island -- in approving civil unions, according to lobby group Human Rights Campaign.
"The Colorado legislature has taken a definitive step forward in the march toward equality," said HRC head Chad Griffin after Tuesday's vote in the western US state.
"The passage of civil unions in the Centennial State is further proof that full equality for committed and loving gay and lesbian couples is in sight," he added.
On the federal level, President Barack Obama's administration has joined an unlikely coalition including major corporations, Republican lawmakers and Clint Eastwood in urging the US Supreme Court to legalize gay marriage.
The nine Supreme Court justices, who rule on some of the most divisive issues in American society, will take up cases on March 26 and 27 dealing with the long-sensitive question.
Some 47 percent of Americans approve of same-sex marriage compared to 43 percent who oppose it, according to a Quinnipiac University poll published last week.
Fifty-four percent of Catholics support same-sex marriage while just 38 percent are opposed, according to the poll, published as the Roman Catholic Church prepared to choose a new Pope.