On average the hypothalamic nucleus IHAH3 is 21.5 times larger in the male brain. The corpus callosum and the anterior commissure are relatively larger in the female brain. (Carter, Rita. Mapping the Mind. CA: University of California Press, 1998, p 71)

The hypothalamus in the brain releases a hormone that controls sex hormones in both men and women. (Stump, Jane Barr, PhD. What’s the Difference? NY: William Morrow and Company, Inc., 1985, p 53)

The third interstitial nucleus of the anterior hypothalamus is of similar size in the brains of females and homosexual males; twice as large in heterosexual males. (Howard, Pierce J., PhD. The Owner’s Manual for The Brain. GA: Bard Press, 1994, 2000. p 223-226)

The hypothalamus in the male brain is five times larger than it is in females. (Tanenbaum, Joe. Male & Female Realities. NV: Robert Erdmann Publishing, 1990. p 53)

The preoptic anterior nucleus seems to regulate functions such as mounting in response to female signals. In humans this area of the hypothalamus is about twice as large in males as in females. (Wilson, Glenn. The Great Sex Divide.England: Peter Owen Publishers, 1989. p 35-36)