Brain Structures Differ Based on Gender, Sex & Sexual Orientation

Of the 4 cell groups of the interstitial nuclei of the anterior hypothalamus, the 3rd group ( in the preoptic-anterior hypothalamic area—or PO-AHA), is referred to as being responsible for sexual dimorphism in reference to sexual orientation. INAH-3 is generally found to be larger in the male brain than the female brain; however, this study indicates the region is smaller, in general, in homosexual males than in heterosexual males.