Brainpower as easy as X and Y
(CNN) -- It's an argument that's as old as it is contentious: that male and female brains work differently.
It's also spawned countless self-help books (think "Men Are From Mars, Women Are From Venus") and bland jokes about women being unable to read maps, or men never asking for directions.
It's a brave expert who'll chart a course through these controversial waters.
But that hasn't stopped Michael Gurian, psychologist and author of "What Could He Be Thinking?".
He believes there are about a hundred structural differences that have been identified between the male and female brain.
"Men, because we tend to compartmentalize our communication into a smaller part of the brain, we tend to be better at getting right to the issue," he said.
"The more female brain (will) gather a lot of material, gather a lot of information, feel a lot, hear a lot, sense a lot," he said.
Scientists say males have more activity in mechanical centers of the brain, whereas females show more activity in verbal and emotional centers.
The differences can be noticed from early childhood, Gurian said, such as when an adult gives a child a doll.
"That doll becomes life-like to that girl, but you give it to a two-year-old boy and you are more likely, not all the time, but you are more likely than not to see that boy try to take the head off the doll," he said.
"He thinks spatial-mechanical. He's using the doll as an object".
To find out why these differences exist, scientists have taken voyages deep inside the gray matter using MRI scans.
The scans show that in most women, the corpus callosum area, which handles communication between the brain's two "hemispheres", is larger.
In layman's terms, it means that the two sides of the female brain "talk" better to each other -- which could explain why studies show women tend to multi-task better.
On the other hand, the scans show men tend to move information more easily within each hemisphere.
It all boils down to genes, according to Dr. Marianne Legato Partnership for Gender Specific Medicine Columbia University.
Women are born with two X chromosomes, and men with an X and a Y.
"And on that Y chromosome are at least 21 unique genes unique to males which control many of the body's operations down to the level of the cells," Dr Legato said.
She also said those genetic differences explain other differences, like why men can drink more alcohol than women without becoming intoxicated.
"Women do not have the enzyme in their stomach that degrades alcohol which men have," she said.
Unfortunately it doesn't explain why some men leave the toilet seat up, or some women can't take out the garbage.
CNN's Elizabeth Cohen contributed to this report.