Intelligence: is there a sex difference in IQ scores?

Arising from: S. Blinkhorn Nature 438, 31-32 (2005); Blinkhorn replies. Steve Blinkhorncriticizes our study of samples of university students, in which we found that the average IQ of men is 4.6 points higher than that of women, as measured by the Progressive (or Raven's) Matrices. He maintains that there is a negligible sex difference in adult intelligence. We believe that the principal error of Blinkhorn's criticism is that he does not consider our result in the context of several other studies showing that adult males have an IQ advantage of around 4-6 IQ points.