DENVER -- The Colorado Supreme Court cleared the way Tuesday for an anti-abortion group to collect signatures for a ballot measure that would define a fertilized egg as a person.

The court approved the language of the proposal, rejecting a challenge from abortion-rights supporters who argued it was misleading and dealt with more than one subject in violation of the state constitution.

If approved by voters, the measure would give fertilized eggs the state constitutional protections of inalienable rights, justice and due process.

"Proponents of this initiative have publicly stated that the goal is to make all abortion illegal -- but nothing in the language of the initiative or its title even mentions abortion," Kathryn Wittneben of NARAL Pro-Choice Colorado said in a statement. "If that's not misleading, I don't know what is."

Wittneben said a NARAL board member was one if six people who challenged the State Title Board's July approval of the initiative's language.

Proponents, led by 20-year-old Kristi Burton, of Peyton, argue that the initiative would simply define a human.

"It's very clearly a single subject," Burton said. "If it's a human being, it's a person, and hey, they deserve equal rights under our law."

Burton and her group, Colorado for Equal Rights, now must collect 76,000 signatures to get the measure on the ballot.

Supporters have six months to gather the necessary signatures, but it was not immediately clear if the clock began running Tuesday or at an earlier milestone.

Wittneben and others said the measure would have deep effects that would hamper in-vitro fertilization and stem cell research and would effectively ban birth control.

Burton disagreed.

"It doesn't outlaw abortion, it doesn't regulate birth control," Burton said. "It's just a constitutional principle. We're laying a foundation that every life deserves protection.

"We'll see what happens after that," she added.