Fiorina, the former Hewlett-Packard CEO, said a recent Planned Parenthood video shows a "fully formed fetus on the table, with its heart beating, its legs kicking."

"Anyone who has watched this video tape, I dare Hillary Clinton, Barack Obama, to watch these tapes. Watch a fully formed fetus on the table, its heart beating, its legs kicking, while someone says we have to keep it alive to harvest its brain," Fiorina said.

Fiorina was referring to a video released by the anti-abortion group the Center for Medical Progress last month, in which a former worker for StemExpress, a biomedical research company, says she saw a fully formed fetus's heart beating.

"This is the most gestated fetus and closest thing to a baby I've ever seen," Holly O'Donnell, a former procurement technician for StemExpress, said in the video. "I'm sitting here looking at this fetus and its heart is beating and I don't know what to do."

The clip does show what appears to be a fully formed fetus on an operating table with its legs twitching. But the clip Fiorina references is not part of the CMP sting video but was instead taken by another anti-abortion group that was added to the sting video. The Center for Medical Progress, however, doesn't explain where the fetus video was shot, so it's not clear whether it was taken at a Planned Parenthood clinic. For its part, the women's health organization has flatly denied the accusations.

RELATED: GOP seeks plan to avoid shutdown, defund Planned Parenthood

Republican candidates also shared whether they would be willing to move toward a government shutdown in order to to defund Planned Parenthood, currently an objective of some hardline conservative leaders. Ohio Gov. John Kasich said he wouldn't be willing to risk that shutdown as he doubts it would be successful in defunding the women's health organization.

For his part, Christie claimed that as "the brand new first ever pro-life governor of New Jersey," he repeatedly defunded Planned Parenthood.

He has indeed vetoed funding for Planned Parenthood repeatedly during his governorship. But it hasn't always been because of his unimpeachable anti-abortion bona fides.

Christie blocked $7.5 million in New Jersey for women's health and family planning services in 2010, during the midst of the recession, but his veto statement didn't emphasize it was out of a total respect for life.

"The State of New Jersey continues to confront unprecedented financial difficulties. Due to the economic crisis, my Administration was forced to make tough decisions," he wrote in a veto statement, trying to address an $11 billion budget shortfall.

CNN's Eugene Scott contributed to this report.