COLUMBIA - Abortions should be banned when a fetus reaches 20 weeks, and doctors who perform such procedures should face criminal prosecution, according to an S.C. House bill that was discussed Thursday.

The 20-week mark is significant, anti-abortion advocates say, because it marks the point when a fetus can feel pain. That notion was disputed at a House subcommittee hearing by pro-abortion-rights advocates who say that abortions at 20 weeks are rare - 1 percent of all abortions, they said. Such procedures, they say, are generally dictated by medical necessity.

The current state standard is 24 weeks unless the life of the mother is in danger, a baby is considered full term at 39 weeks.

The idea of the unborn child experiencing pain was a powerful argument for anti-abortion lawmakers. "As a mother of five, I understand wanting to protect my children from pain," said Rep. Wendy K. Nanney, R-Greenville, the sponsor of the bill, H.B. 4223. "That's what a mother does."

The bill has more than 30 sponsors.

A House subcommittee opted to hear more testimony when the committee meets again. A date has not yet been scheduled. Committee members said that when they reconvene, they expect the bill to advance.

Anti-abortion advocates said the bill - along with similar measures in other states - is an effort to chip away at the landmark Supreme Court decision of Roe v. Wade, the 1973 case that deemed abortion a fundamental right.

Nanney said in an interview that new science about pregnancy is changing the legal and healthcare landscape.

"I think we're realizing that a body can feel pain in the womb," she said. "It will somewhat change Roe v. Wade down the road, I hope."

Pro-abortion-rights advocates said the bill is a dangerous attempt for politicians to step into a conversation that should be left between a doctor and a patient.

"While women should not have to justify their personal medical decisions, the reality is that abortion later in pregnancy is very rare and often happens under heartbreaking and tragic circumstances," Sloane Whelan, an S.C. Planned Parenthood spokeswoman, said in an emailed statement. "Representative Nanney is using junk science to push a dangerous and extreme bill that doctors and experts agree has no basis in medicine."

The bill says that doctors who perform such procedures could face a felony charge, but it doesn't define it any further or specify jail time or penalties. That's one of several changes and revisions committee members plan to make as the bill advances, said Rep. J. Derham Cole, R-Spartanburg, who chairs the House Judiciary subcommittee.

Rep. Ronnie Sabb, D-Williamsburg, sought to have speakers and Nanney acknowledge that the science indicating when a fetus can feel pain is disputed. He also noted that the bill does not make any exception for rape or incest.

Nanney said that in most of those cases, most abortions would have occurred by 20 weeks.

Pro-abortion-rights advocates called the proposed ban unconstitutional. Similar 20-week bans have been passed in 13 states, according to Planned Parenthood. The law is being challenged in Georgia, Arizona and Idaho.

Anti-abortion advocates were already predicting a court fight that they hope would be settled by a favorable Supreme Court. Mary Spaulding Balch, the National Right to Life Committee's legislative director, testified Thursday, and read opinions from U.S. Supreme Court Justice Anthony Kennedy, the court's key swing vote.

She said that recent opinions on abortion issues suggest an opening. Balch, a lawyer, said that she believes that there is a state's rights legal argument when it comes to abortion that she and others hope to advance. "The state would have more room to protect the unborn child," Balch said. "If we were to get this case in the Supreme Court I think we would have five votes."