Her team has looked at nearly 2,000 healthy people, including kids, teens, and young adults who took various tests of their mental skills. Differences in their "brain road maps" (scientifically known as "the connectome") can explain why males outperform females on certain tests of mental skills, while females have the edge in others.

"Our studies are finding significant differences in the brain circuitry of men and women, even when they're doing the same thing: It's like two people driving from Philadelphia to New York, who take different routes, but end up at the same place," says Ragini Verma, PhD, associate professor at the University of Pennsylvania in Philadelphia.

Who Is Better?

Women have more connections going left and right across the two halves of the brain. This could give them an advantage in pulling together information from different sources and drawing conclusions. The left half of the brain handles logical thinking, and the right is associated with intuition.

Men's brains have more connections from front to back, which may heighten their perception. They may be more attuned to what's going on around them so they can take action. Men have stronger connections between brain areas for motor and spatial skills. That means males tend to do a better job at tasks that need hand-eye coordination and understanding where objects are in space, such as throwing a ball or hammering a nail.

On average, male brains are about 10% larger than female brains. "However, bigger doesn't mean smarter," says Daniel Amen, MD, author of Unleash the Power of the Female Brain. He's studied more than 45,000 brain scans. "And no differences have been found in men and women's IQs, regardless of brain size."

MRIs showed the biggest gaps between the sexes were the larger amount of gray matter women had in their hippocampus, a structure that plays a role in memory, and the left caudate, which is thought to control our communication skills. Verma found that in female brains, there's more wiring in regions linked to memory and social cognition. So is it surprising that women tend to be better at understanding how other people are feeling and knowing the right way to respond in social situations?

Not only could recent findings change how scientists study the brain, but this research could also have important health benefits, like better treatments for disorders that affect one sex more than the other.