It's correlated to learning disorders because of the high number of disordered people who are cross dominated, it's hard to say if cross dom is a by-product of disability, or if disability it is a by-product of cross dom. One theory on suggests that it's harder for a cross dom because their hemispheres are fighting for dominance, and that there's a lot of chaotic firing when both hemispheres are equal. I suppose it would depend on the skill of the person, can your brain sift through the extra chaos? Although I've also heard that cross dom has a higher rate of disability, it also has a higher rate of genius.
I'm right eye, right leg, right ear, and left arm dominant. I'm mostly ambidextrous with my arms, eyes, and ears (only minor preferences), but my foot is solidly right.
Left hand - writes, draws, plays music, golfs, hockey, and fires a bow.
Right hand - tennis, throws, punches, fires a gun, and is generally stronger.
I can throw with both basically equal, right is only 5mph faster, and punching is easy to switch on.