Is it true that guys believe they're smarter than they really are? Or that girls talk more than guys? Do mosquitoes bite guys more than girls? Which sex is better at diapering babies, remembering birthdays, or hammering nails? These are just some of the questions to which you'll find some pretty astounding answers. Using scientific research, author Michael J. Rosen explores the ways in which environment and experience, as well as neurology, physiology, and genetics come together to shape personality and gender behavior in both expected and unexpected ways.