Factors that may influence brain gender development

Current clinical evidence suggests that brain development progresses from the prenatal to the perinatal period, attaining approximate adult dimensions and mass within 3-4 years. The gender of a brain is established during the prenatal-postnatal stages, with manifestation of sexual behaviors emerging later after puberty. Most the majority of research on gender dimorphism and sexual orientation of the brain has focused on the prenatal period, while data concerning the postnatal stage remain sparse. This review summarizes data regarding brain gender development, dimorphism and sex orientation, and proposes that circumstantial factors, such as chemicals and stress during the newborn and postnatal periods may affect gender and sexual behaviors in adulthood. More studies will be essential to fully understand the effects of environmental influences on brain gender development.