Mothers who smoke heavily during pregnancy are more likely to give birth to children who grow up to become career criminals, research has suggested.
The experts from the Harvard School of Public Health in the US found heavy smoking was linked to offending, regardless of whether the child was raised in socially deprived circumstances.
The risk was raised for women who smoked 20 or more cigarettes a day during pregnancy, according to the research published in the Journal of Epidemiology and Community Health. The study involved more than 3,700 mothers between 1959 and 1966 and studied their smoking habits during pregnancy.
Criminal checks were carried out on the offspring of the mothers when the children were aged at least 33 in 1999/2000.
The results showed that those children whose mothers smoked heavily were 31% more likely to have been arrested as those whose mothers never smoked, and were more likely to be repeat criminal offenders.
The findings were the same for both men and women.
The authors said their findings "suggest that the elevated risk of offending is independent of other family attributes more common among women who smoke during pregnancy, such as a history of mental illness and lower socio-economic status, and may be directly attributable to the smoking exposure.
"While we cannot definitively conclude that maternal smoking during pregnancy (particularly heavy smoking) is a causal risk factor for adult criminal offending, the current findings do support a modest causal relationship."
The authors point to plausible evidence for the biological impact of nicotine on the developing brain of babies.