Alcohol can be purchased legally in the United Kingdom from 18 years of age. For the present paper, we analysed data on adolescents under the legal age. Our sample therefore consisted of 862 twin pairs (142 male, 185 female MZ twin pairs and 108 male, 141 female, 286 opposite sex DZ twin pairs) and 1629 individuals (complete data on both twins were not always available) aged 11–17 years (mean = 15.33 years; SD = 1.41).
