"Open almost any issue of a scientific journal in education or developmental psychology or sociology, and you will find paper after paper announcing correlations between parental characteristics and child development outcomes. Parental income and child brain structure. Maternal depression and child intelligence. Each of these papers represents a massive amount of investigator time and public investment in the research process, and each of these papers has, in Freese's words, an 'incisive, significant, and easily explained flaw'—that differences in children's environments are entangled with the genetic differences between them, but no serious effort is being expended toward disentangling them." Kathryn Paige Harden