The contentious question about whether a fertilized human egg is a person will go before the U.S. Supreme Court.
A national anti-abortion group said it has appealed the Oklahoma Supreme Court decision rejecting a citizens petition calling for a statewide vote on the question.
The Oklahoma court ruled in April that the petition was unconstitutional, citing federal court precedents in abortion cases.
Keith Mason, founder of Personhood USA, said the appeal is based on the argument that Oklahoma voters have a constitutional right to express their preference "on such a critical issue as life."
Personhood USA's Initiative Petition 395 seeks to amend the Oklahoma Constitution to define a fertilized human embryo as a person.
"It is the first time Personhood is knocking on the door of the Supreme Court," said Mason.
The high court could reject the appeal outright or agree to hear arguments in the case, then render a decision.
Details for this story were provided by the Ada, Okla., News.