It's common to hear people complain about George Bush that he owes everything he has achieved in his life to his family. So this study reported in the New York Times was interesting:
His astonishing assertion: differences between families explain only 25 percent of the nation's income inequality; the remaining 75 percent is explained by differences between siblings.According to the article, it seems as if the research stands so far; the weakness is primarily in the fact that he doesn't explain well what is responsible for differences. He doesn't reject the idea that forces outside our control are partly responsible for success or failure...
Some of his more provocative findings concern middle-borns. In families with three or more children, Mr. Conley says, middle offspring are less likely to receive financial support for their education and may do less well in school than their older and younger siblings. The chances that a second child will attend private school drop by 25 percent with the birth of a third, Mr. Conley found, and the likelihood that he or she will be held back a year increased severalfold. Unlike typical first- and last-borns, he reasons, middle children never experience family life as an only child; instead, they are forced to compete with their siblings for money and attention. (In this sense, he concedes, birth order does matter: not as a psychological variable but as a constraint on family resources.)...but his overall research does suggest that there are many factors, and pre-existing income inequality is only a small part.