Why are some people left-handed? Over the years there have been dozens of hypotheses as to what determines 'handedness', however it remains a puzzle. A popular hypothesis was that since the right and left sides of the body are controlled by the opposite hemispheres of the brain, people whose right hemisphere is larger than the left would be left-handed.
But studies show the area of the brain which controls speech and muscular co-ordination is almost always better developed in the left hemisphere, even in people who are left-handed.
Archaeological evidence has shown that the majority of mankind has been left-handed for more than a million years. That said, Asians are less likely to be left-handed than whites or blacks (9.3 per cent against 11 per cent) and men are more likely to be left-handed than women.
There is evidence which suggests handedness is hereditary, however it is not clear whether it is due to genetics or parents teaching their children to be right- or left-handed.
Studies have claimed to prove a link between being left-handed and being artistic - think of Leonardo da Vinci, Raphael, Michelangelo, Picasso. Musical left-handers include Beethoven and two of the Beatles - Paul McCartney and Ringo Starr.
Other studies have claimed to find links between being left-handed and being gifted. Albert Einstein and Isaac Newton are just two of the left-handers who have contributed to science.
Famous actors who are left- handed include Charlie Chaplin, Tom Cruise, Robert DeNiro, Bruce Willis and his former spouse, Demi Moore.