Lesbian's Brain Reaction To Pheromones Similar to the Heterosexual Male Brain, May 15, 2006

Pheromones, sexual chemicals, trigger responses in lesbians which are different from those of heterosexual women, heterosexual men and homosexual men, according to a new study at the Stockholm Brain Institute.

The researchers used Positron Emission Tomography (PET) to study the sexuality by watching responses within the brains of twelve lesbian women.

In a previous study, which had looked at heterosexual and homosexual men, the researchers found that the Anterior Hypothalamus brain area was activated when exposed to AND (progesterone derivative 4,16-androstadien-3-one). AND is much more abundant in male sweat than female sweat - ten times more. Heterosexual men's Anterior Hypothalamus area was also activated when exposed to EST (estra-1,3,5(10),16-tetraen-3-ol), a female hormone, found in abundance in pregnant women's urine.

The Hypothalamus region triggers our endocrine system - hormones. It responds to pheromones, chemicals which are thought to trigger sexual responses in humans and animals.

Dr. Ivanka Savic, team leader, and her team found that lesbian women's Anterior Hypothalamus area became activated when exposed to both EST and AND in a similar, but not identical, way to heterosexual men's. However, the researchers said it seems homosexuality is different in men and women.

The researchers found that the lesbian women processed the AND pheronome through the olfactory network, unlike heterosexual women who did so via the anterior hypothalamus.