It is news to no one that men and women are different. We just are. Our bodies are obviously different; our behavior is different, and, as it turns out, our brains are different too. And if our brains are different, then we might even speculate that how we learn and think about new information might be different as well. But how exactly? This, of course, is the perplexing bit.

For those involved in the debate-and make no mistake, there is a far-reaching debate-the real question is how might a clearer understanding of how men's and women's brain differ affect the way we live as a society? There are those who believe that a better understanding could lead to changes in such areas of life as health care, law and education.

The search for brain differences is nothing new; the modern (and more sophisticated) version of this idea has been with us at least since the 1960s, when researchers first discovered that a part of the hypothalamus called the preoptic area, was substantially larger in males than females. Since then, more differences have been found in the topographies of the male and female brain. The search for such variability between the male and female brain has stepped up in the last fifteen years, as imaging technology has made the pursuit easier.

In the 1990s-the Decade of the Brain-results streamed in from every quarter about brain differences. In one of many such studies, University of Cincinnati Medical Center neurologist Dr. Gabrielle de Courten-Myers found in 1999 that men have more neurons in the cerebral cortex and women have more of something called neuropil, a substance containing the structures necessary for cell-to-cell communication.

But what do we make of these and other brain differences?

The truth is, it is hard to say. These differences are morphological, or structural, and just about everyone admits that one of the real mysteries of the brain is in understanding the relationship between morphology and function.