PORTSMOUTH — There has been intense public scrutiny of a bill under discussion in the Massachusetts Legislature that would ban spanking children.

The bill was submitted by Kathleen Wolf, a nurse who lives in Arlington, Mass. She said her intention is not to punish parents, but to urge state officials to take a stand against corporal punishment in Massachusetts. Wolf concedes the bill has no chance of becoming law, but her goal is to educate parents so that they and the parents of the future learn better methods for disciplining children.

"We pass the behavior down from generation to generation," Wolf said. "If we are not taught options, we draw on that experience. We need to offer education so people can develop other options."

Wolf and clinical psychologist Theresa Whitehurst testified in favor of the bill before the Massachusetts House on Wednesday. The bill was filed by Rep. Jay Kaufman on Wolf's behalf.

Professor Murray Straus, co-director of the Family Research Laboratory and professor of sociology at the University of New Hampshire, said he agrees with Wolf. A top researcher in his field, Straus has studied spanking by examining large and representative samples of American parents since 1969. He is the author of "Beating the Devil Out of Them: Corporal Punishment in American Families and Its Effects on Children."

He supports legislation against corporal punishment of children. He said spanking is not effective as a disciplinary tool and that the harm it causes is reason enough to abandon it.

"I think it's a very important thing to do, based on a large amount of research," Straus said. "One review of 119 studies found a 93 percent agreement in the results, showing the harmful effects of spanking. There is nothing else in child research where the results are so consistent and yet are ignored. There is a cultural myth that spanking may sometimes be necessary."

The bill has sparked a debate in the Bay State. Evelyn Reilly, of the Massachusetts Family Institute, said parents — not lawmakers — should decide when to spank.

"Many children need to know there is someone in charge," she said. "It gives them a sense of security to know that there is someone who is willing, even though reluctantly, to administer a non-injurious, judicious spanking."

Straus said if a 2-year-old sticks his hand near a hot stove, parents should rush and grab the child, not spank him.

"Tell them you'll get hurt, don't do it," he said. "Your body language and the tone of your voice will communicate that this is something to not do. Swatting is likely to interfere with learning because the hurt is coming from mom."

Plus, Straus said, it's stressful to be hit, and the experts know that stress interferes with learning. He said there is no research to prove that spanking is likely to interfere with or change a child's behavior.

"Parents committed to spanking will say, 'I told her not to do this and she's doing it again and again, so I have to do something about it,'" Straus said. Spanking is used, but not because other methods are less effective. The problem is that it takes repetition to learn at the toddler age.

"The recidivism rate for a 2-year-old is high," he said. "About 50 percent will repeat the behavior in two hours and 80 percent within a day. That also applies to spanking. With a 2-year-old, nothing works, but actually they all work; it just takes many repetitions. However, though all work, spanking is less effective in the long run and has harmful side effects."

Straus said legislation is needed, even with the risk of it being abused.

"We legislate lots about families that we think will be harmful," Straus said. "We ban marriage below a certain age because we think it's harmful. Some women claim rape when none took place, but we still need rape laws. People will use the law to their advantages. It's a human characteristic, but some things we need to put up with for the larger benefit. The problem is, people don't believe spanking is harmful."

Straus said he has reviewed parenting books for decades and, on average, they didn't mention spanking or maybe had half a page in a 500-page book.

"And not a single one recommended not spanking," he said. "It's as though there was a public health book that did not mention the harm of smoking."

The research clearly shows the gains from spanking come at a big cost, Straus said. These include weakening the tie between children and parents and increasing the probability that the child will hit other children or their parents and, as adults, hit a dating or marital partner. Spanking also slows down mental development and lowers the probability of a child doing well in school, he said.

"One would be hard-pressed to find another aspect of parenting and child behavior where the results are so consistent," he said.

Material from The Associated Press was used in this report.