Why are some people left handed?

One theory centers on the two halves of the brain, i.e. the left half and the right half, each of which functions differently. Medical science believes that the left half of the brain predominates over the right half. the fact is that nerves from the brain cross over at neck-level to the opposite side of the body, and nerves from the other side of the brain reciprocate. The end result is that the opposite sides of the body are supplied by the opposite sides of the brain.

The predominant left half of the brain, which graciously supplies the right half of the body, theoretically renders it more skillful in reading, writing, speaking, and working, and makes most people right-handed. "Lefties," however, are the product of an inversion, whereas the right half of the brain predominates, and they work best with the left side of their bodies