Our brain has right half and a left half, which function in differently. It is believed that in most cases, the left half of the brain is predominant over the right half.
This helps the right half of the body to work more skillfully. We read, write, speak and work with the left half of our brain. It makes most of us right handed too.
But in the case of left handed people, its just the opposite. The right half of the brain is predominant and the person works best with the left side of his body, making him left handed.
Below Left Handed info from Wikipedia (Read More):-
In 1998, a study suggested that approximately 7 to 10 percent of the adult population was left-handed, and that left-handedness is more common in males than females.[2] Left-handedness, in comparison to the general population, also appears to occur more frequently in both identical and fraternal twins,[3][4] and several groups of individuals with neurological disorders (such as people with epilepsy,[5] Down Syndrome,[6] autism,[7] mental retardation[8] and dyslexia). Statistically, the identical twin of a left-handed person has a 76 percent chance of being left-handed, identifying the causes as partly genetic and partly environmental.
http://en.wikipedia.org/wiki/Left-handedness
