MONTREAL, Jan. 7 (UPI) -- Dutch and Canadian researchers have linked aggression in children to their mothers smoking during pregnancy.
The study, published in Development and Psychopathology, also finds the risk of giving birth to aggressive children increases among smoking mothers whose familial income is less than $40,000. Another risk factor for aggressive behavior in offspring was smoking mothers with a history of antisocial behaviors such as run-ins with the law, dropping out of high school or using illegal drugs.
"Mothers-to-be whose lives have been marked by anti-social behavior have a 67 percent chance to have a physically aggressive child if they smoke 10 cigarettes a day while pregnant, compared with 16 percent for those who are non-smokers or who smoke fewer than 10 cigarettes a day," study co-author Dr. Jean Seguin of the University of Montreal said in a statement. "Smoking also seems to be an aggravating factor, although less pronounced, in mothers whose anti-social behavior is negligible or zero."
The research was part of a wider investigation of children, which examined behaviors of 1,745 children between the age of 18 months to three and a half years. Aggressive offspring were characterized by their mothers as quick to hit, bite, kick, fight and bully others.