Development of the cerebral cortex: XI. Sexual dimorphism in the brain.

Do sexual differences in the organization of the brain exist, and if so, why? Are they caused by environment or genetics? In fact, the evidence for sexual dimorphism in the brain is compelling. In many animals, distinct differences between sexes in brain morphology have been found that are believed to be responsible for a number of the observed behavioral differences between the sexes. How do these differences arise and affect behavior? Many result from the differential expression of gonadal steroid hormones during early critical periods of brain development.