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 by both parents. Fifty-nine percent of the sample was adopted with 66% of these adoptions originating from South Korea; 94% of the non-adopted adolescents are Caucasian.
