Women Have More
Frontal Lobe Neurons Than Men

By Ellen Kuwana
Neuroscience for Kids Staff Writer
December 7, 2001

Although each person looks different on the outside, we are quite similar on the inside -- or are we? Canadian researcher Sandra Witelson presented evidence at the 2001 Society for Neuroscience meeting that shows women's brains have more nerve cells in their frontal lobes than men's brains.

Dr. Witelson should know. Not only did she examine Albert Einstein's brain, she oversees a brain "bank" at McMaster University in Ontario, Canada. Since 1977, she has collected hundreds of brain specimens for study. What makes this brain collection special is that the people who donated their brains were neurologically normal -- that is, they died of causes such as lung cancer that did not directly affect the brain. Also, the donors were interviewed to establish a profile of their cognitive abilities. This makes the anatomical information extremely valuable because it can be matched with a person's cognitive profile.

By examining 20 brains (11 female, 9 male) from the "bank," Witleson and her group found that women were able to pack approximately 18% more nerve cells into areas of the prefrontal lobes; the prefrontal lobes help regulate higher functions such as language, judgment, and planning future actions. Although women start out with more cells in these areas, by old age, men and women have similar number of cells in the frontal lobes. This is because women lose cells in these areas faster as they age than men do. This may contribute to the higher incidence of Alzheimer's disease in women.

At birth, boys' brains are bigger by weight than girls' brains (upper chart). If you measured around a boy's head, say as if to fit him for a hat, the boy's head would be approximately 2% larger around than a girl's head. In adults, men's brains still weigh more than women's -- approximately 11% more (upper chart). Men's heads are still 2% larger around than women's heads. As adults, men generally weigh more than women and are taller. If you take body size into account, the brain size differences are small (see bottom chart, which shows brain weight as a percentage of body weight).

Perhaps the greater cell density in women's prefrontal lobes compensates for the smaller brain size. Despite these differences, men and women perform equally at most tasks. So even though men may have bigger brains and women have more cells in some critical areas, neither can point to these facts as a measure of greater intelligence. Judging who is smarter is much more complex than finding out who has the largest brain.

Brain Weight

(Data from Dekaban, A.S. and Sadowsky, D., Changes in brain weights during the span of human life: relation of brain weights to body heights and body weights, Ann. Neurology, 4:345-356, 1978)

Did you know?

There are approximately 24 brain banks in the world.


  1. Witelson, S.F., Kigar, D.L., and Stoner-Beresh, H.J. Sex difference in the numerical density of neurons in the pyramidal layers of human prefontal cortex: a stereologic study. Soc. Neurosci. Abstr., Vol. 27, Program No. 80.18, 2001.
  2. Women Have More Brain Cells - BBC News article, November 13, 2001.
  3. Comparative Neuroanatomy - Neuroscience for Kids
  4. Male versus Female Brains - Neuroscience for Kids

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