evidence for qualitative sex differences in genetic effects for AUDs. Specifically, the ratio of the correlation between opposite-sex and same-sex twin pairs did not differ significantly from unity (rg-mf = 1, 95% CI 0.42–1.00, χ2 = 1.79, df = 4, p = 0.77), albeit with very large CIs, which suggests that the same genes contribute to AUD risk in both males and females.
