DENVER — A proposed state constitutional amendment defining a fertilized human egg as a person was certified Thursday for the November ballot, moving Colorado a step closer to an election battle over abortion rights.
Secretary of State Mike Coffman said backers of the proposal turned in an estimated 103,000 valid signatures, far more than the 76,000 required.
Kristi Burton, the prime mover behind the measure, said her group, Colorado for Equal Rights, will target voters who personally oppose abortion but don't want to impose their views on others.
Burton said polling shows those voters make up about 20 percent of the electorate.
"Our job is to put the truth out there for the voters," she said. "Science is on our side."
Opponents say the proposed amendment could affect birth control because the most widely used form of contraception works by preventing fertilized eggs from attaching to the uterus.
They also say the measure could deter in-vitro fertilization and stem cell research and bar doctors from treating women with some forms of cancer.
"Defining an egg as a person in our constitution and statutes isn't science-based and makes bad public policy," said Crystal Clinkenbeard, a spokeswoman for an organization called Protect Families Protect Choices, which opposes the measure.
Clinkenbeard said her group has no plans to challenge the signatures but will campaign against the measure.
"We've decided to challenge it in the court of public opinion," she said, adding that Colorado voters have rejected measures that would "restrict health care access and place the government in the midst of private decisions."
Colorado for Equal Rights turned in a total of 130,000 signatures. Coffman's office determined that about 103,000 were valid, based on an examination of a computer-selected random sample of roughly 6,500 signatures or 5 percent of the total.
Coffman's spokesman, Rich Coolidge, said state law established the sampling method for verifying signatures.