NYT article on left-handedness
Found this on the New York Times website, interesting read for an insight in to the understandings, and there seem to be several, of left-handedness.
http://query.nytimes.com/gst/fullpage.html?res=9A01E1D6103BF935A25756C0A9669C8B63&sec=&spon=&pagewanted=print
The article is 7 years old, I'll see if I can dig up anything more current than this.