Seems to me we did a poll on this once before.
Some more info has become available. The estimated incidence of left-handedness in the general population is 10%.
For decades, scientists have postulated that left-handedness is associated with autoimmune diseases such as type 1 diabetes. The phenomenon that more left-handed people have diabetes is restricted to type 1 diabetes, according to published scientific data.
The frequency of autoimmune disease reported by the left-handed subjects in one study done in England and Scotland was slightly more than two times greater in both geographic groups of left-handers, according to the study. The researchers also found a higher likelihood of an autoimmune disease in the first- and second-degree relatives of the left-handed subjects compared to those of the right-handed subjects.
Dr. Searleman and a colleague considered the theory that left-handedness is associated with autoimmune disorders by comparing the handedness of people with type 1 or type 2 diabetes, Crohn's disease or ulcerative colitis against a healthy control group. They did find a significant connection between left-handedness and Crohn's disease or ulcerative colitis, but no connection with diabetes. They did note, however, that males with type 1 diabetes were slightly more likely to be left-handed than males with type 2.
Some people are like Slinkies... Not really good for anything, but they still bring a smile to your face when you push them down a flight of stairs.