Estrogen Link In Male Aggression Sheds New Light On Sex-specific Behaviors
ScienceDaily (Oct. 2, 2009) — Territorial behavior in male mice might be linked to more "girl-power" than ever suspected, according to new findings at UCSF. For the first time, researchers have identified networks of nerve cells in the brain that are associated with how male mice defend their territory and have shown that these cells are controlled by the female hormone estrogen.
It seems that estrogen and not testosterone makes males more territorial and aggressive. Neonatal exposure to estrogen causes physical changes in the adult brain related to territorial behavior. Females with increased neonatal estrogen exposure exhibited lower libido and increased territorial behavior to the point of chasing males away. That is for mice... but is it the same for humans?
... So what about the humans? I have a hypothesis regarding the Middle East. It has been a hotbed of hate and war for over 3000 years. Perhaps one of the contributors to this territorial violence is a diet (I don't know their diet) that is rich in phytoestrogens. That might be enough to alter the neonatal brain development making them more territorial and aggressive.