A Colorado Senate panel on Monday will consider a bill that offers gay and lesbian couples many of the benefits and responsibilities of marriage, the AP reported.

Openly gay state Senator Pat Steadman introduced his gay-inclusive civil unions bill on Valentine's Day.

Democratic Representative Mark Ferrandino will sponsor a similar bill in the House.

The Senate Judiciary Committee begins debate on the measure Monday.

Steadman said he is proposing the law because a 2006 voter-approved constitutional amendment bans gay marriage in the state.

“The constitutional amendment was about marriage and that's not what this bill is about,” Steadman told NBC affiliate 9 News. “The importance of this issue is that there are literally thousands of families in Colorado that currently do not have the equal protection of state law that are available to others.”

All 20 Democratic members of the Senate are co-sponsors to the legislation, making passage in the Democrat-controlled chamber a near certainty. Less certain are the bill's prospects in the House, where Republicans hold a single seat majority.

At a rally on Thursday, faith leaders showed support for civil unions.

“This bill is not about morality. It's not about religion. It's not about faith. It's about basic civil rights,” said Rabbi Joseph Black from Temple Emanuel in Denver, the Colorado Independent reported.

“For too long the loudest voice from the religious community in regards to [the] GLBT community has been that of condemnation and denunciation and that needs to change. You're going to be hearing opposition to this bill from faith communities and we just wanted you to know that's not the only voice that's out there.”

The Roman Catholic Church is one of those faith communities opposed to the bill.

In a letter to Colorado Catholics, Rev. Charles J. Chaput, the Archbishop of Denver, said the bill “undermines the privileged place of marriage and the family.”

“Marriage and the family are cornerstones of any culture – Christian or not. They ensure the future through the creation of new human life. Any diminishment of the identity of marriage and the family undermines society itself.”

If approved, Colorado would become the fourth state to offer the union behind New Jersey, Illinois and Hawaii.