9 out of 10 people, all over the world, are right-handed. True ambidexterity occurs in less than 1% of the population. Why does the world skew to the right? Scientists still don’t know.
Things like nipples and nostrils come in pairs on the outside of our bodies, but it doesn’t work that way in the interior: The heart and spleen, for example, normally form on the body’s left side, while the liver forms on the right; each lung has a distinctly different shape. We’re asymmetrical INSIDE.
Our brain halves are different too: the left side is more logical, while the right hemisphere is more creative and intuitive (although that pattern is reversed for lefties).