The analyses reported in this paper used a subset of the full sample. Adolescents were included if at least one parent was ever diagnosed with nicotine dependence and used tobacco within their child's lifetime (ever exposed), or if both parents were never diagnosed with nicotine dependence and never used tobacco within their child's lifetime (never exposed). A total of 335 adolescents, with data available on both parents, were excluded based on these criteria. For an additional 112 adolescents, data for one parent was missing, and the other parent did not meet the inclusion criteria. Adolescents excluded because of missing data did not significantly differ from those included on number of disruptive disorder symptoms or measures of lifetime substance use. The final sample included 785 adolescents from 402 families, whose mean age was 14.9 years (SD = 1.9 years). Of these, 414 (53%) had at least one parent who was nicotine dependent and used tobacco during the adolescent's lifetime. Ninety-three adolescents (23%) were exposed by their mother only, 229 (55%) were exposed by their father only, and 92 (22%) were exposed
