Obama adviser John P. Holdren wrote in his book "Human Econolgy: Problems and Solutions" that children in big families have lower IQs.
“It surely is no accident that so many of the most successful individuals are first or only children,” wrote Holdren and the Ehrlichs, “nor that children of large families (particularly with more than four children), whatever their economic status, on the average perform less well in school and show lower I.Q. scores than their peers from small families.”
Holdren and the Ehrlichs published "Human Ecology" with W.H. Freeman and Company in 1973. In June 2000, a study published in American Pyschologist debunked the notion that children in larger families have lower I.Q.s. But when Holdren appeared in the Senate Commerce, Science and Transportation Committee in 2009 for a confirmation hearing on his appointment to run the White House Office of Science and Technology Policy, he continued to argue for the benefits of “smaller families” on other bases.