Comments on an article by Leah S. Richmond-Rakerd et al. (see record 2014-01638-027). Richmond-Rakerd et al.'s paper makes a substantial contribution to the study of common genetic and environmental influences on the onset of drinking and gambling combined. In this clear and meticulous analysis, the age of first drinking (AFD) and the age of first gambling (AFG) were assessed in a large cohort of twins in two different set-points. It was reported that AFD and AFG are influenced by separate and unique environmental factors as well as genetic and environmental substrata of both phenotypes, which are dissimilar in men and women. These findings are in line with previous studies on the onset of substance use, which stated that environmental factors contribute to drinking onset. Richmond-Rakerd et al. highlighted the importance of genetic and environmental overlap between drinking and gambling onset, considering that both behaviors could be correlated with later risk of developing a pathological gambling and alcohol dependence. The authors described that one of the limitations of their study is the generalizability of their results, due to the widespread availability of gambling in their country. Prospective studies comparing interventions that aim at delaying drinking and gambling initiation should also take into consideration the results of Richmond-Rakerd et al.'s study.