''why'' children likely use drugs grow could children modelling parents' behaviour equally plausible could children inherited drug use predisposing genes parent put increased risk drug use adults regardless parents' behaviour adoption studies parse relative effects rearing environment genetic inheritance find small negligible effect rearing environment smoking alcohol marijuana use adopted children ref name keyeslegrand ref larger effect rearing environment harder drug use ref name kendlersundquist ref
Natural science Biology Genetics Behavioural genetics