Advances in our understanding of sex differences in neuroscience provide new opportunities to study the role of genetic factors that may underlie mental disorders and their core components. For example, McCarthy and colleagues 32 have provided a scholarly summary of our understanding of the role of sex hormones and immunological factors in the establishment of brain differences across development, and sex differences in regional brain volumes due to differential cell death, neuronal and glial genesis, dendritic branching and synaptic patterning between males and females. There are several strategies that may be employed to identify the role of genetic and environmental factors in the core domains underlying mental disorders. By integrating advances in neuroscience to study hypotheses for sex differences we can glean more information about how the sex differences in the brain lead to different sex ratios in complex disorders. Moreover, these studies may aid in identifying critical periods of risk, when exposure to environmental factors may influence genetic susceptibility factors, such as the prenatal period for neurodevelopmental disorders, middle childhood for ADHD, and adolescence and early adulthood for mood
