Gender and sex is in the brain
in one of those accidents of science, scientists working on the influence of
sex differences in gene expression, chanced upon regions of brain that radically
influences the gender distinction in experimental rats.
Researchers of The Ohio State Universityunder the leadership of Kathryn Lenz, an assistant professor of psychology and neuroscience, found that the key to gender distinction reside in certain immune cells in the brain, the so called mast cellsthat are part of the hypothalamus, those cells that are oft-ignored by the neuroscientists, those cells that are held responsible also for allergic responses, The results are published in the Journal of Neuroscience.
Male rats with silenced mast cells did not show typical male sexual expressions like chasing and mounting female rats and were far less interested than typical males, acting almost like females. Brain-manipulated female rats on the other hand acted like males.
If what is observed in rats could be extrapolated to humans, it would imply that relatively minor influences - such as an allergic reaction, injury or inflammation during pregnancy - could steer sexual behavior development in offspring, the researchers fear. It's even conceivable that taking antihistamines or pain relievers during pregnancy could play a role, they surmise.
Furthermore, this discovery could help explain risks for psychiatric and neurological disorders that are more common in males, including autism, hopes the researchers.