Offspring ever smokers were not at increased genetic risk for smoking relative to never smokers. However, offspring regular smoking was associated with maternal low HSI (OR=1.70; 95%CI:1.08–2.67) and offspring ND was associated with having a father who was ND and mother with high HSI (OR=2.13; 95%CI:1.25–3.63; and OR=1.80; 95%CI:1.10–2.94, respectively).