Further research will likely change what we know today, but this is our current knowledge:
Total brain size: Male brains weigh about 11% more than females’. This is necessary because men’s larger muscle mass and body size require more neurons to control them. This does not suggest that men are smarter than women.
Cell numbers: Men have 4% more brain cells and 100 grams more brain tissue. This may explain why women are more prone to dementia because although both may lose the same number of neurons due to disease, males have a greater functional reserve.
Corpus callosum: The corpus callosum moves data between the right and left hemisphere. The research here is mixed. Some studies say that it is bigger and more developed in women; other studies find no differences.
Hypothalamus: This portion of the brain is twice as large in heterosexual men than in women and homosexual men, pointing toward a biological basis for homosexuality and heterosexuality.
Language: For men, language is most often just in the dominant hemisphere (usually the left side), but a larger number of women seem to be able to use both sides for language. If a woman has a stroke on one side of the brain, she may still retain some language from the other side. Interestingly, people who use pictographic written languages (Chinese, Japanese, Korean) tend to use both sides of the brain regardless of gender.
Inferior Parietal Lobule: This region is significantly larger in men. This is an interesting area because it is linked to a trait we often think of as both male (mathematical intelligence) and female (emotional intelligence).
Limbic size: Females have larger deep limbic systems, the part of the brain that controls emotion. Women, on average, are more in touch with their feelings and are generally better able to express their feelings. They have an increased ability to bond and be connected to others. However, they are more susceptible to depression, especially at times of significant hormonal changes and attempt suicide three times more than men. Yet men kill themselves three times more than women, in part because they use more violent means and in part because they are generally less connected to others, increasing their risk of completed suicides.
Three Types of Brains?
So far we’ve been talking about two types of brains, but not so fast. Simon Baron-Cohen of Cambridge University (and the cousin of Sacha Baron-Cohen AKA Borat) posits three common brain types:
- The “female brain” for individuals where empathizing is stronger than systemizing.
- The “male brain” for individuals where systemizing is stronger than empathizing.
- The ‘balanced brain’ for individuals who are equally strong in their systemizing and empathizing.
A key feature of this theory is that your gender cannot tell you which type of brain you have. Not all men have the male brain and not all women have the female brain. Males and females differ in what they are drawn to and what they find easy, but both sexes have their strengths and weakness. Neither sex is superior overall.
Interestingly, when we deliberately change sex-role behavior, say, men become more nurturing or women more aggressive, our hormones and even our brains respond by changing too.
–Simon Baron-Cohen, The Guardian, 4-17-2003
–Neuroscience for Kids, 2008