Position Emission Tomography (PET) and Functional Magnetic Resonance Imaging (fMRI) have allowed us to distinguish sexually dimorphic areas in the human brain. This can possibly explain certain differences in traits and behavioral tendencies between men and women.
· The temporal lobe of the brain is quite different for males and females. In general, among females, there is greater density of the neurons in that area (associated with language development and processing).
· The corpus collosum is larger in female brains. This brain structure facilitates the communication between the hemispheres of the brain. (This may be considered supportive argument for the idea that females easily blend emotions and logic. Many will argue this is advantage, while others consider it a weakness.)
· The overall size of the cerebral cortex, however, is larger in males. It has more neurons and is, somewhat, more complex. In fact, both female and male babies have the same number/amount of neurons, but the process of programmed cell death (apoptosis) continues longer in females. The bigger size of the cerebral cortex in males is only natural, considering males are generally bigger, compared to females. Within the animal kingdom, larger brain size infers more complex cognitive functioning and behavior. Within the same species, however, this general law does not apply. Bigger brain by no means implies being more intelligent.
· There is a sexually dimorphic nucleus in the anterior hypothalamus that is larger (more neurons) and denser in males. This area is believed to contribute to the control of sexual behavior, but the correlation is not quite well explained yet. The female hypothalamus has developed to generate menstrual cycle, which, itself, helps explain many of the differences between males and females.