DENVER—The origins of Utah State House Bill 12 lie in an act of dark and desperate violence.

Last May in a small town in eastern Utah, a 17-year-old girl, seven months pregnant, paid a man she had just met $150 to beat her up in hopes of inducing a miscarriage that would resolve her crisis. He obliged, taking her to a basement and kicking her repeatedly in the abdomen.

The fetus survived the assault and was born in August. The attacker went to jail. And the girl, whose name was never released because she was underage, became the center of a legal debate—and the piece of legislation awaiting the governor's signature or veto. The bill would formally criminalize what she did, that is, to seek an illegal abortion.

If it is signed into law by Gov. Gary R. Herbert, a Republican, who has said he agrees generally with its goals but is still studying the particulars, Utah would still allow legal abortions performed by a doctor. But it would go further than any other state, several legal experts said, in mapping out a much murkier question: When is a woman criminally liable for trying to end a pregnancy through other means or self-infliction?

The bill's sponsor, Rep. Carl D. Wimmer, a Republican and former police officer from the suburbs of Salt Lake City, said the beating case, and the decision by a judge last fall that the girl had committed no crime because seeking an abortion is not illegal, revealed “;a loophole”; in the law.

“;A woman going out to seek any way to kill her unborn child, no matter how heinous or brutal, couldn't be held liable,”; Wimmer said.

But critics say legislation inspired by an unusual, perhaps even freakish criminal case, could open up the difficult question of intent and responsibility, and give local prosecutors huge new powers to inquire about a woman's intentions toward her unborn child.

For example, if a pregnant woman gets into a vehicle, goes on a wild ride way over the speed limit without wearing a seatbelt and crashes and the fetus is killed, is she a reckless driver? Or is she a reckless mother-to-be who criminally ignored the safety of her fetus?

Under the bill, a woman guilty of criminal homicide of her fetus could be punished by up to life in prison.

“;So many things can happen, and it's all in the eye of the beholder—that's what's very dangerous about this legislation,”; said Marina Lowe, the legislative and policy counsel to the American Civil Liberties Union of Utah, which urged Herbert to veto the bill.

Some women's advocacy groups say the bill simply codifies what many states are already doing, using existing laws about the unborn to prosecute apparently errant mothers.

Last month in Iowa, for example, a pregnant woman who fell down the stairs at home confided to emergency workers that she was not sure she really wanted to have her child. Though the woman did not immediately miscarry from the fall, she was arrested anyway under a state law that makes it a criminal act to harm a fetus. She was released after two days in jail, and charges were dropped.

At least 38 states have laws against fetal homicide, generally intended to create additional penalties when a pregnant woman is assaulted or killed. And two states, Delaware and New York, also have laws specifically making self-abortion a crime. Both laws were passed before the U.S. Supreme Court decision in Roe v. Wade.

Some opponents of abortion also do not like the Utah bill because of the very fact that it does codify the language and limits of abortion law, with specific delineations about when ending a pregnancy in Utah is legal and when it is not.

“;Well, it's all right to kill a human being in this case, but not in this case,”; said Jim Sedlak, vice president of the American Life League, a national group that works for what it calls “;pro-life concerns.”;

“;I would urge him to not sign this law and to send it back,”; Sedlak said, referring to Herbert. “;He should ask the Legislature to address the real problem of personhood in the womb.”;

Whether the bill, if it does become law, would be a rarely used symbolic declaration or a widely used law enforcement tool is part of the debate as well.

“;Prosecutors have a lot of discretion, and miscarriage is a sad but common event in connection with pregnancy,”; said Nancy Northup, president of the Center for Reproductive Rights, a nonprofit advocacy group for birth control and abortion rights. “;This bill would cast suspicion, potentially, on every single miscarriage.”;

Nonsense, said Wimmer, the sponsor. He said the language in the bill requiring “;intentional, knowing or reckless”; acts by a woman against her unborn child sets a high bar that would only allow questions to be asked in the most glaring of cases.

Behavior by a mother that might harm but not kill her fetus, including use of alcohol or tobacco, would not be covered by the bill, he said. But, he added, a mother who killed her fetus by taking illegal drugs might conceivably be charged.

The 17-year-old girl's child, meanwhile, was adopted by a Utah couple.

Supporters of the bill said a letter from the baby's adoptive mother, read aloud by Wimmer at a legislative hearing on the bill, was a powerful emotional moment that may have swung some votes.

The bill was ultimately approved by overwhelming majorities in the Republican-controlled Legislature: 59-12 in the House and 24-4 in the Senate.

“;When Rep. Wimmer read the letter, about the little girl playing with bubbles in the bathtub and learning to crawl and so full of life, you could have heard a pin drop,”; said Laura Bunker, director of United Families Utah, a group that worked on behalf of the bill. “;And all of a sudden people realized that there was a victim here, and the victim was alive and had a future.”;

Lynn M. Paltrow, executive director of National Advocates for Pregnant Women, a nonprofit group based in New York, said the focus on the child obscured the bleak story of the teenager, who also deserves, she said, empathy from the world, and the law.

“;Almost nobody is speaking for her,”; Paltrow said. “;Why would a young woman get to a point of such desperation that she would invite violence against herself? Anybody that desperate is not going to be deterred by this statute.”;