WASHINGTON -- Republican presidential candidate Newt Gingrich clarified his position on personhood Friday when he told ABC News' Jake Tapper that he believes life actually begins at "successful implantation," not fertilization.
"I think the question of being implanted is a very big question," Gingrich said. "My friends who have ideological positions that sound good don't then follow through the logic of 'So how many additional potential lives are they talking about? What are they going to do as a practical matter to make this real?'"
He said that "when a woman has a fertilized egg and that's been successfully implanted, that now you're dealing with life." Otherwise, Gingrich noted, "you're going to open up an extraordinary range of very difficult questions."
Gingrich's latest remarks on when life begins expand on comments he made during the Thanksgiving Family Forum in Iowa last month, when he said he would support a federal personhood amendment defining life at conception.
Conception, by definition, involves "fertilization or implantation or both," so Gingrich's comments over Thanksgiving don't necessarily conflict with the position he stated Friday. But the national movement led by Personhood USA takes the position that a zygote should be given full legal rights at the moment of fertilization.
"If Newt Gingrich believes that life begins at implantation, he is scientifically incorrect," Jennifer Mason, a spokeswoman for Personhood USA, told HuffPost on Friday. "Any human embryology textbook confirms that life begins at the moment of fertilization. From that moment, there is a living, growing, developing human being."
If taken literally, a personhood law defining life at fertilization, like the legislation that was recently rejected in Mississippi, could ban certain kinds of birth control, in vitro fertilization and stem cell research in addition to criminalizing abortion. It could also have a host of legal consequences beyond women's reproductive health.
GOP presidential candidates are split on the issue. Former Utah Gov. Jon Huntsman said in November that the personhood movement "goes too far" by seeking to prohibit abortion in cases of rape and incest and when the life of the mother is in danger. But Rep. Michele Bachmann (R-Minn.) co-sponsored the proposed Life At Conception Act in January, which would define life from the moment of fertilization.
Other candidates have been less clear in their views. Former Massachusetts Gov. Mitt Romney said that he is "supportive of efforts to ensure recognition that life begins at conception," but that the issue should be left up to the states. Texas Gov. Rick Perry recently dodged a question about personhood at a town hall event in Kansas, and Herman Cain said in October that he believes life begins at conception but it's "not the government's role ... to make that decision."
A spokesperson for the American Congress of Gynecologists and Obstetricians said that pregnancy is not scientifically established until the fertilized egg is implanted in the lining of the uterus -- which supports Gingrich's position.
But personhood advocates are not persuaded by the doctors.
"The question of personhood is not when life begins -- that is a settled scientific fact," Mason said. "The question is whether we believe that all human beings have human rights."
UPDATE: 4 p.m. -- Michele Bachmann issued the following statement on Friday in response to Newt Gingrich's comment that life begins at implantation:
"Newt Gingrich stated today that life begins at implantation, not at conception. But those who are truly involved in the life issue know that life begins at conception. Additionally, the former Speaker's description of the life issue as 'practical' is a rejection of the most sacred principle that each and every life has value, a principle recognized by our founders in the Declaration of Independence of the most basic right with which every human is endowed. This along with his inconsistent record on life is just one more indication that Newt is not dedicated to protecting the lives of the unborn and doesn't share the most basic of conservative principles.
"While Newt has presumptively declared himself the nominee, I believe the people of Iowa and all Americans will reject any candidate who fails to understand when life begins and that protecting it is the top priority for conservatives. I'll always side with life. I signed the Susan B. Anthony pledge and believe that my word means something. That's why I have fought to protect life from conception until natural death. And as president, I'll defund Planned Parenthood and make sure that not one dime of taxpayer money goes to pay for abortions here in the United States or internationally."
Read the GOP presidential candidates' views on reproductive rights: