Upbringing affects opportunity. Upper-middle-class homes are not only richer (with two professional incomes) and more stable; they are also more nurturing. In the 1970s there were practically no class differences in the amount of time that parents spent talking, reading and playing with toddlers. Now the children of college-educated parents receive 50% more of what Robert Putnam calls “Goodnight Moon” time (after a popular book for infants).
(Putnam reports in his book “Our Kids” that) educated parents engage in a non-stop Socratic dialogue with their children, helping them to make up their own minds about right and wrong, true and false, wise and foolish. This is exhausting, so it helps to have a reliable spouse with whom to share the burden, not to mention cleaners, nannies and cash for trips to the theatre.
Working-class parents, who have less spare capacity, are more likely to demand that their kids simply obey them. In the short run this saves time; in the long run it prevents the kids from learning to organise their own lives or think for themselves. Poor parenting is thus a barrier to social mobility, and is becoming more so as the world grows more complex and the rewards for superior cognitive skills increase.