Men are from Mars and women are from Venus, a bestselling book claims. Science does confirm, though, that male and female brains are wired differently — but what that means is the focus of a great deal of research.
One recent study found that structurally, it's rare to have a brain with all "male" or "female" traits.
However, that doesn't mean that there aren't differences in our brains, other researchers say.
"One could go on and list hundreds of anatomical and chemical differences between the brains of men and women, and this would be true in other animals as well," said McMaster University brain researcher Prof. Sandra Witelson.
Her McMaster lab contains a collection of over 100 brains — including Albert Einstein's.
The differences between men's and women's brains — especially in the language and speech regions — interest her greatly. Her studies revolve around brain lateralization — anatomical and functional differences between people's right and left cerebral hemispheres just above the ears, and their degree of connection.
"It appears that there is a more generalized interconnectivity in the female brain than in the male brain," she said. "A male brain is more specialized, has more independent modules. I think it's more vulnerable. And I think it has the potential for less plasticity."
Dr. Apostolos Georgopoulos is the director of the Brain Science Centre at the Minneapolis VA Medical Center, a large veterans' hospital in Minnesota, where he and his colleagues are measuring the brain waves and cognitive skills of hundreds of healthy women ranging in age from 30 to over 100. Other studies are being carried out on men.
"Women's brains are definitely different from men's brains," said Apostolos. "What we have found is that women, in many different tasks, process information about five times faster than men, and use much less of their brain to do identical cognitive performance."
But apparently, female brain speed and efficiency come at a cost.
"Women seem to use certain parts of their brain much more efficiently, but if these are hit they're in big trouble," Apostolos said, suggesting that men's brains may be better able to compensate for damage.
But Witelson points out that men's brains are vulnerable too. She says at the tender age of five weeks, male embryos get doused in testosterone, changing them and their brains forever.
"The male brain has undergone a sexual differentiation," she said. "And if something should go wrong, it could affect the male brain more than the female brain."
Science is just beginning to plumb the diversity of networks in people's brains — each as unique as its owner's DNA.
How the hundred billion neurons in an adult brain get hard-wired — differently so in men and women — how neural circuits determine sexual or gender identity, recover from damage or age healthily all remain tantalizing mysteries for now.