In my continuing quest to unravel the genetic mystery of my son’s wet ear wax, cloverleaf tongue-folding ability, and shovel-shaped teeth I stumbled across John H. McDonald’s “Myths of Human Genetics.” He describes that while tongue-rolling and other traits are common examples used by teachers for basic genetics, those traits aren’t all simply expressed by dominant/recessive genes. Tongue-rolling is partially genetic but studies have found non-rolling parents with rolling kids. So it’s not a good basic example though it’s often used in introductions to genetics. Among his many well laid out examples is my nemesis, yes the wet earwax, which is one that actually is a simple dominant/recessive situation but isn’t used much as an intro example, likely because of homogenous school populations and grossness.