National Geographic has an article with a theory about lefties-vs-righties, entitled LEFTIES SURVIVE (BARELY) DUE TO ELEMENT OF SURPRISE?
Left-handed people have disadvantages. Over the years, lefties are more apt to suffer from schizophrenia, epilepsy, autism, or have learning disabilities. They are more likely to have a serious accident, as most of the world is designed around righties. Male lefties are also shorter, on average.
However, scientists have determined that lefties carry with them the ability to throw the other 90% of the world off their guard. This is why left-handed people are often more successful in sports competition versus the more common right-handed folks. Baseball pitchers, batters, tennis players, boxers – the left-handed ones are often prized and in high-demand.
They also say that left-handed men earn more than right-handed men, on average. Lefties also have better coordination, and often have IQs higher than 131.