Ah! I get to plug one of my favorite websites, OMIM (Online Mendelian Inheritance in Man): http://www.omim.org http://www.omim.org Their article on left handed

Ah! I get to plug one of my favorite websites, OMIM (Online Mendelian Inheritance in Man): http://www.omim.org http://www.omim.org Their article on left handedness goes into great detail as to the biology behind hand preference. In short, it's related to brain patterning and the direction the hair on your head swirls (seriously!): http://omim.org/entry/139900 http://omim.org/entry/139900 As for the evolutionary reason, the most recent research suggests that it may have to do with cooperation. Simply put, it's easier to cooperate when everyone (or most everyone) uses the same hand for most activities. More details here: http://www.northwestern.edu/newscenter/stories/2012/04/left-handed-minority.html http://www.northwestern.edu/newscenter/stories/2012/04/left-...