DENVER -- Colorado’s most conservative lawmakers signed petitions Monday supporting the Colorado Human Life Amendment to the state Constitution.

The group Colorado for Equal Rights needs 76,000 signatures by May 13.

Kristi Burton, a spokesperson for the group, estimated they have gathered about 40,000 signatures. She thinks they will meet the required number to put the issue on the November ballot.

The amendment would define life as beginning at the time a woman’s egg is fertilized.

It doesn’t specifically mention abortion, but many think the new definition would lead to legislation to try to outlaw abortions in Colorado or build a test case that could be taken to the United States Supreme Court.

Cal Zestro spends almost every day gathering signatures or working the phones to try and build support for the petition drive.

He told 7NEWS, "I think the law should protect everybody."

Monday, the petition drive picked up the signatures of some of Colorado's most conservative political leaders.

A public vote is a way to get around the legislature which has historically protected abortion rights and contraceptive choices.

State Sen. Greg Brophy Wray said, "Clearly it’s always the right time to take the stand for the sanctity of life."

A similar amendment is being proposed in Montana.

Proponents have tried but failed to pass Personhood Laws in Georgia, Mississippi and Michigan.

Abortion rights groups are watching the petition process closely and said they are prepared for a battle if the amendment gets on the November ballot.

Jody Berger of Colorado Planned Parenthood thinks the issue will fail in a statewide race.

"It is an extreme law that goes too far. People recognize that,” Berger said.