Gay marriage advocates in Colorado are trying to overturn a state constitutional amendment recognizing traditional marriage.
If they're successful, the measure would appear on a statewide ballot in 2012. Supporters would have to collect around 86,000 signatures to put the question to voters.
The proposal would reverse the 2006 state amendment that said only a union of one man and one woman would be a valid marriage.
Aurora college student Mark Olmstead, who is gay, is behind the effort.
"I just want to draw attention to the issue," he told The Denver Post. "Hopefully, that will bring in some sort of fundraising."
Similar efforts to change the Centennial State's constitution have been attempted before. The most recent was in 2009.
Carrie Gordon Earll, spokeswoman for CitizenLink, the policy arm of Focus on the Family, told the newspaper she doesn't believe the ballot initiative has a chance.
"Every time the definition of marriage has gone to the voters - 31 times to date - voters have affirmed marriage as one man and one woman," she said in a statement.
"We have every confidence that the people of Colorado would affirm that vote again," she said.