Estrogenic Regulation of Social Behavior and Sexually Dimorphic Brain Formation

•Gonadal hormones affect the morphology of sexually dimorphic nuclei (SDNs) of the brain.•The BNSTp contains not only a male-dominant subregion but also a female-dominant subregion.•ERα and ERβ may have opposing effects on the estrogenic regulation of sex-typical social behaviors.•Both genomic and non-genomic signaling by estrogens regulate social recognition and learning.•Spinogenesis may be a critical mechanism by which estrogens, via ERs, regulates social behaviors.