Family-based quasi experimental designs are well-suited to testing gene by environmental exposures of the type seen where offspring outcome may be influenced by both genetic factors and environmental prenatal exposure (D’Onofrio et al., 2013). Comparisons of siblings with varying levels of prenatal cigarette exposure have indicated that the relationship between prenatal cigarette exposure and offspring substance use outcomes are not significantly linked, suggesting that the association between prenatal exposure to cigarettes and offspring substance use problems is more likely due to familial background factors rather than a direct causal influence of prenatal exposure (D’Onofrio et al., 2012, Ellingson et al., 2012). However, this approach has not been utilized to study the effects of prenatal alcohol exposure.
