The contrast in birth rates in England and Wales between the periods on either side of the peak in 1964 is described and its components discussed. The drop after 1964 is mainly due to a drop in marital fertility at all ages, and especially the youngest. There is, however, as yet no evidence for a fall in the completed fertility of recent cohorts although their birth intervals are clearly lengthening. The mechanisms of such a change are described and their relative importance suggested. It is concluded that ultimate responsibility for the changing tempo of recent British fertility lies with fluctuations in the economic situation of the country.

This paper attempts a new look at an old problem. Throughout this century there have been many reports showing that certain characteristics of family structure are associated with the individual's performance in evaluative situations, be these IQ tests, tests of achievement, school and university examinations and even occupational success (for an excellent summary, see Anastasi, 1956). It is well known, for example, that children from large families tend not to do so well in such situations as children from small families, and that this phenomenon appears to be, in some degree, independent of socio-economic differences. This we can illustrate with our own data (Text-fig. 1) in which we see a steady decline in score on a nonverbal group test of intelligence as the size of the family increases. Less clear is whether other features of family composition, such as the spacing between siblings, the sex composition of the sibship and the ordinal position of the individual within the sibship, also affect achievement. (There is no lack of reports but, as we shall show, the evidence they provide is conflicting.)

I am honoured to be asked to give the Galton Lecture and, as an obstetrician, I am particularly glad to give it in the context of this symposium devoted to biosocial aspects of fertility.

By comparison with the frightening problems of population control on a world scale, the control of Britain's population should be easy but, unfortunately, it has not been tackled with the urgency it demands. In the North East of Scotland, however, considerable progress has been made. We have a natural human laboratory for the study of this problem and other aspects of human reproduction. It has the advantage of relative isolation, homogeneous population, convenient size (half a million) and availability of scientific personnel from Research Institutes, University and National Health Service. In addition, very good relations exist between these bodies and the general public. Continuity of medical care facilitates long-term study of patients, assessment of needs and results of treatment. The people have become knowledgeable and co-operative.

When the first Eugenics Society Symposium (Meade & Parkes, 1965) was held in 1964, its final session, on ‘Aspects of Fertility Control’, included two papers (Peberdy, 1965; Morgan, 1965) describing experimental family planning services, which offered advice and treatment in their own homes to the ‘problem parents’ of large families in the lower working class. These two projects, established from 1959 onwards in Newcastle and Southampton, together with a similar service pioneered in York by Dr Dronfield, have been used as models for subsequent ‘domiciliary family planning services’, and an account of one (Brittan, 1964) has been reprinted by the FPA as an information leaflet.