However, this is only one part of the story. Pregnant women who smoke may differ from those who do not smoke on several environmental and genetic variables. The decision not to quit smoking during pregnancy may be related to antisocial traits, risk-seeking behavior, or a reduced attention to one’s own and the child’s well-being. These traits may reflect a familial vulnerability to bipolar disorder, which is transmitted to the offspring. Furthermore, there may be a relationship between maternal smoking during pregnancy and rearing behavior, psychosocial stress, family conflict, and paternal psychiatric history. Smoking during pregnancy is often associated with the use of other substances (such as alcohol) as well as with postnatal smoking. It is also well documented that low education level and economic disadvantage are overrepresented among women who do not quit smoking during pregnancy. In the Talati et al. study, several potential confounders were adjusted for (including maternal psychiatric history), and some variables did not differentiate smoking from nonsmoking mothers (e.g., educational level), but several other variables could not be controlled for (such as maternal personality traits, family history of mental disorders, and smoking after pregnancy). Of note, women smoking in the period 1959–1966, when recruitment for the study took place, were somewhat early adopters, in whom some of the above-mentioned confounding personality traits may have been overrepresented. Furthermore, the study did not explore paternal personal and family psychiatric history.