A second issue concerns the specificity of the risk represented by smoking parents. Previous research suggests that smoking is, in part, an expression of a broad vulnerability to engage in disinhibited behavior, which is distinguished more generally by undersocialized conduct and low levels of dispositional constraint 8, 9. Evidence from twin studies suggests that this broad vulnerability may be genetically transmitted from parent to child10. From this perspective, familial resemblance for disinhibition is general rather than disorder specific. Thus, non-adoptive parents who engage in behavior like smoking may also transmit a non-specific genetic risk that increases the likelihood that their offspring will engage in tobacco use as well as other forms of disinhibited behavior11. Of course this risk would not be present in the adoptive families.
