In this study, we compare the effect of being exposed to a non-adoptive parent who smokes, reflecting both genetic and environmental risk, to the effect of being exposed to an adoptive parent who smokes, reflecting environmental risk only. To examine the specificity of the risk, we included a diverse array of adolescent outcomes, both behavioral and dispositional, that tap vulnerability to disinhibition. Figure 1 provides a schematic overview of our adoption design and hypotheses. We hypothesize that exposure to parent smoking represents a specific environmental risk for adolescent tobacco use. Additionally, we hypothesize that non-adoptive parents who smoke may also transmit a non-specific genetic risk for disinhibited behavior not limited to tobacco use. Thus we expect to observe increased tobacco use among both the non-adoptive and adoptive offspring of smoking parents, but increased rates of other disinhibited behavior in the non-adoptive offspring only.
