And if you think that's what * should * happen you can start to think there's something wrong with you or your baby when it could just be normal human variation. (askmoxie.org)
Location, location, location Human variation depends on a collection of random mutations across the genome, contributing to differences in appearance as well as behavior. (scientificamerican.com)
All individual human variation amounts to just one - tenth of 1 percent of the entire genome. (discovermagazine.com)