In 1932 all 11-year-old children in Scottish schools were given a group intelligence test, and a sample of 1000 was individually tested. The future careers of this sample were followed till 1939. In 1968, 709 of the original sample could be traced, and data about education, employment, and family were obtained. In 1947, a parallel survey was conducted in Scotland, and a sample of 1208 children was individually tested, and followed up for 16 years. The same data about education, employment and family are available for the 1947 Sample.A comparison between length of school education indicates a greater proportion completing a full secondary education in the 1947 than in the 1932 Sample. Proportionally, more of the 1947 Sample graduated from university. In marriage, it is possible to cut across the 1932 Sample at the age of 27 years, to make direct comparison with the 1947 Sample at the same age. The greatest incidence of marriage is in the middle range of IQ, but later records for the 1932 Sample show a relative uniformity of marriage over the IQ range. The pattern for occupational class is similar. There is a slight tendency to later marriage in the 1932 Sample. Two measures of differential fertility for IQ are used. For both samples, there is a negative relationship between the mean IQs of the sample members and the number of their sibs, more marked for the 1947 Sample. The number of children born to members of the two samples before the age of 27 years shows a similar relationship, but in the following 20 years the pattern for the 1932 Sample changes to one with a peak of mean IQ at two children. It is suggested that linear differential fertility for IQ may be a function of the age of the parent.