Origins of Sex Differentiation of Brain and Behavior

Abstract

Sex differences in adult brain and behavior are often established early in development when the brain is remarkably immature. In adults sex differences take on many forms including latent variables, dimorphisms, frequency, and more. Androgens and estrogens from the developing male fetal testis masculinize the brain, so that physiology and behavior are in synchrony and harmony with gonadal phenotype. This differentiation process occurs during a critical window in males, but females remain sensitive to exogenous steroid treatment for a longer developmental period. The cellular mechanisms of sexual differentiation are diverse but often involve inflammatory signaling molecules and immune cells. This may have consequences for the higher vulnerability of males to neurological and neuropsychiatric disorders of development.