This article reviews sex studies of children of cousin marriages and three studies of children of incestuous matings. It is argued that these studies, taken as a whole, provide no substantial evidence for an inbreeding depression effect within the polygenic system commonly asserted to determine IQ. (Author/DB)

Wolff has recently reinterpreted the data of Lee to indicate that Black migration from the south to Philadelphia had been selective in an IQ-relevant manner. However, Wolff's deduction from Lee's data is shown to depend entirely upon an assumption about cumulative IQ deficit in southern Black children. (Author/CTM)