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Old 03-13-2016, 04:28 AM
engineer_comp_geek engineer_comp_geek is offline
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Coincidentally, I was just reading about this the other day.

Scientists have recently (with the past couple of years) discovered a group of genes that play a large role in handedness. Some of these genes are also responsible for our body's asymmetry. So you're kinda on the right track, except that a more asymmetric body related to limb size is probably more of a result of those same genes that cause left handedness rather than actually being a cause of left handedness.

Some of those genes are also related to things like Situs Inversus, which is when your organs are flipped from normal (your heart is on the right instead of the left, and you liver is on the left instead of the right, etc). Lefties also tend to have a slightly larger Corpus Callosum, which is the thick bundle of nerves that connects the left and right hemispheres of your brain. This is again caused by that same group of genes.