Head reveals your hand

Now you can tell which hand a person writes with - simply by looking at their hair.

If you are right-handed, the hair at the back of your head will grow in a clockwise direction.

However, if you are lefthanded, it could grow in either direction. And for those with curly hair, the direction of the curls could also reveal your preferred hand.

Researchers made the discovery while looking for genetic differences in right and left handers. They believe the hair whorl, the medical term for the place at the back of the head where hair appears to spiral from, is formed in a similar part of the embryo to the brain and nervous system. This means it reflects our "handedness".

Dr Amar Klar of America's National Cancer Institute in Maryland studied 500 people as part of his team's research. After ruling out the long-haired and bald, he found more than 95 per cent of right-handers' hair grows in a clockwise whorl on the scalp. The locks of lefties and the ambidextrous coil either way.

He said: "It is certainly possible to make a very accurate guess at which hand somebody writes with by looking at their head. Medically, this is also important as it reveals a lot about how the brain develops, and which parts of the body develop along with it. It is actually a very good indicator of brain symmetry."

The research could have a serious benefit in revealing why some people are lefthanded. It could help treat diseases caused by abnormalities in brain symmetry like autism, schizophrenia and dyslexia.

People assume there is no single handedness gene because it is not inherited. Two left-handed parents often have right-handed children. But some families, including the Royal Family seem to have several left handers. The Queen Mother was lefthanded, as are The Queen, Prince Charles and Prince William.

Klar believes his hypothesis accounts for these puzzles. If children of left-handers have the "random" gene, they could be left or right-handed.

Dr Clyde Francks studies handedness at the Wellcome Centre in Oxford. He said: "Handedness is important when you look at asymmetry in the brain. In terms of treatment for a lot of serious mental disorders, the more work in this area the better."

Although there are many myths surrounding left handers, a disproportionate number seem to be geniuses, for instance Einstein, Leonardo da Vinci, Michelangelo and Picasso.