Why is it in a right-handed world, left-handed athletes often dominate?

Researchers are using that view to help explain why so few people are left handed.

The researchers say cooperation and competition in human evolution was the reason that some people in the world were left handers.  

The researchers also came up with a mathematical model to support the theory, showing that more than 50 percent of elite baseball players are left handed, while only about 10 percent of the general human population is left handed.