A large and growing body of research is focused on estimating how much of the behavioral trait variation across individuals can be statistically accounted for by genetic factors, including several studies that investigate entrepreneurial behavior. Most of these analyses are twin studies, which estimate the heritability of a trait by comparing the correlation of the trait in monozygotic twin pairs to the correlation in dizygotic twin pairs. Such studies suggest that entrepreneurship and a wide range of other important economic behaviors and outcomes are moderately heritable. Although twin and family studies can establish that genetic factors account for some of the variation in a trait, they do not identify specific genes or the biological pathways through which genes function.