March 14, 1999
Web posted at: 5:58 p.m. EDT (1758 GMT)

ATLANTA (CNN) -- Men whose mothers smoke often during pregnancy may be more prone to violent and criminal behavior than the adult sons of women who abstain from tobacco, according to research published Sunday.

The study is apparently the first to link adult criminal behavior to maternal smoking, researchers said. Other research has investigated a similar link between mothers and their adolescent children.

The more women smoked in their third trimester, the higher the rate of criminal arrests of their male children, said Dr. Patricia Brennan of Emory University in Atlanta.

Emory researchers examined the criminal records of male children born to more than 4,000 women in Denmark who, from 1959 to 1961, kept diaries of their smoking habits while pregnant.

Thirty-four years later, police records of the women's sons showed that only 8 percent of the men born to women who did not smoke were likely to commit a violent crime. That percentage nearly doubled among the adult sons of women who smoked 10 to 20 cigarettes a day, the study showed.

The scientists factored out other possible influences on behavior, including drug use during pregnancy, the father's criminal history and the family's economic status.

"Our results support the hypothesis that maternal smoking during pregnancy is related to increased rates of crime in adult offspring," said the study, published in the March issue of the Archives of General Psychiatry, an American Medical Association publication.

"This general finding is consistent with the literature linking behavior problems, conduct disorder and adolescent offending to prenatal maternal smoking," the report concluded. "Our study extended these findings by showing that maternal smoking is related to persistent offending rather than to adolescent-limited offending."

Damage to the fetus' central nervous system could be the reason for the behavioral effect, researchers speculated. Nicotine may cause changes in the fetal brain that can affect behavior and possibly contribute to aggression.

Compared with males whose mothers did not smoke during the third trimester, males whose mothers smoked more than 20 cigarettes a day during that stage were 1.6 times as likely to be arrested for nonviolent crime, 2.0 times as likely to be arrested for violent crime and 1.8 times as likely to be persistent offenders, the researchers found.

The findings agreed with a 1992 Finnish study that followed 5,996 men for a shorter time, scientists said.

Still, researchers stopped short of claiming a cause-and-effect relationship between maternal smoking and adult male crime.

Just because a woman smokes during pregnancy does not mean her son will commit a violent crime, and crime won't disappear if pregnant women stop smoking, Brennan said.

David Fergusson, a psychiatric epidemiologist at the Christchurch School of Medicine in New Zealand who wrote an editorial accompanying the report, said genetics, not tobacco, could be to blame.

"Mothers who smoke during pregnancy are often young women who have previous misconduct problems, and there is quite an inheritability of misconduct problems," Fergusson said Sunday.

The study did not look at the police records of daughters born to smokers. Researchers said there may not be a similar outcome for adult daughters because, in laboratory tests on animals, the male brain is more reactive to nicotine than the female brain.

Correspondent Holly Firfer and Reuters contributed to this report.