Left-handedness is a rare phenomenon that affects only about 10 percent of the world's population. In celebration of International Left-Handers Day on Aug. 13, take a look at these interesting facts about left-handed people.
1. Between 10-12 percent of people on Earth are left-handed. Women are more likely to be right-handed than men by about 4 percentage points.
2. August 13th is "Left-Hander’s Day." Launched in 1996, this yearly event celebrates left-handedness and raises awareness of the difficulties and frustrations left-handers experience every day in a world designed for right-handers.
3. Five out of the last seven United States presidents were left-hand dominant.
4. James A. Garfield was one of the first left-handed presidents. It was said he could simultaneously write Latin with his right hand and Greek with his left.
5. Mothers who are over 40 at the time of a child's birth are 128 percent more likely to have a left-handed baby than a woman in her 20s.
6. Some scientists have suggested that left-handers were originally in the womb with a twin that did not survive, or a "Vanishing Twin."
7. Research indicates that left-handers are more likely to become schizophrenic, alcoholics and dyslexic. They are also more likely to have Crohn's disease, ulcerative colitis or mental disabilities.
8. While the exact cause of left-handedness is unknown, one theory is that handedness could be a result of genetics.
9. Left-handedness runs in the British royal family. The Queen Mother, Queen Elizabeth II, Prince Charles and Prince William are or were all left-handed.
10. Some scholars say left-handed people generally die nine years earlier than right-handed people.
To get even more interesting facts about left-handed people, click here.
Check out a list of famous left-handed people here.