[RightWhale]

what causes left-handedness

I did not know until age 10, but I am left-handed. But not exclusively. Small-motor control is better in the left. I believe it is genetically caused. Runs in the family.

[Alas Babylon!]

Yup. I'm left handed. And left footed. I kick with my left foot much better than my right. The two hemispheres of the brain control the different sides of the body. The left hemisphere controls the right side, and the right hemisphere controls the left side. That's why they say left handed people are in their "right" minds. Some also say that the left hemisphere controls logic and mathematic skills, while the right hemisphere controls verbal skills and artistic expression.