Children from wealthy households get all the advantages that money can buy, from music lessons to SAT tutors. Although parents might fret over the details of such advantages—is it better to play the piano or the violin?—these details are mostly insignificant, subject to the law of diminishing returns. As the science blogger Razib Kahn notes, "When you remove the environmental variance, the genetic variance remains." These results capture the stunning developmental inequalities that set in almost immediately, so that even the mental ability of 2-year-olds can be profoundly affected by the socio-economic status of their parents. As a result, their genetic potential is held back.