Sex differences in the human brain

At a population level, women and men differ in a wide variety of behavioral traits and in the probabilities of developing certain mental disorders. Some of these sex differences may be related to sexual dimorphism in brain structure, as it emerges during prenatal and post-natal development. Here, I provide a brief overview of the sex-chromosome–specific pathways that underlie sexual dimorphisms in general, describe the most common brain phenotypes derived in vivo with magnetic resonance imaging, discuss the challenges in interpreting these phenotypes vis-à-vis the underlying neurobiology, and, finally, review the known sex differences in brain structure from birth, through adolescence, to adulthood.