In sum, sociological analysis of genetic phenomena represents an exciting and important opportunity. Sociologists are uniquely positioned to comment on social and institutional forces that structure behavioral trends. While they may appear to be unlikely compatriots with geneticists, their expertise in social contexts, such as schools, neighborhoods, workplaces, and families, makes them central to gene–environment interaction studies. The fact that genetic influences on behaviors such as smoking vary not only across social spaces (Boardman 2009; Boardman et al. 2008) but also across historical periods ensures that sociology will have an important voice in the science of genetic association studies. Recently, a number of genetic epidemiologists have called for more thorough accounts of the biology of gene–environment interactions (Rutter 2008). However, it is also clear that testable hypotheses about the biological pathways through which genes operate require a corresponding set of testable hypotheses regarding the social-environmental factors that enable or restrict the influence of genes. This is precisely the type of work that sociologists have engaged in over the past two centuries. If, indeed, the social environment is a fundamental cause
