Chlormadinone acetate (0·5 mg) was given continuously to 200 patients for 1512 cycles in an investigation lasting a little over 2 years. Only a small number of the women stayed in the trial for the whole period. The women were in the reproductive age group and of proved fertility. Lack of cycle control was the chief drawback. However, the majority of the cycles were of normal duration, intensity and flow. Breakthrough bleeding occurred in 3·8% of the total cycles. Of the patients 49% had side effects in 18·6% of the cycles. They were common in the first 3 months but were mild. No pregnancy occurred due to method failure. Six pregnancies occurred due to tablet omission on 2 or more days. A heavy drop-out rate of 78·5% was found. The majority of the patients who dropped out did so for reasons not related to the drug; only 14% of the patients dropped out due to side effects. Vaginal cytohormonal study, premenstrual endometrial biopsies and postcoital tests were carried out during the trial to study the mode of action of the drug.

Using two Gallup polls, which together contained three questions on the attitudes of adult Americans towards population growth and control, a multivariate analysis was conducted of the relationship to each question of nine demographic factors: age, city size, education, family income, occupation of the household head, race, region, religion and sex. Only education and religion showed an intrinsic relationship with attitudes. Specifically, the extent of endorsement of the view that the world population growth rate is a serious problem, and of the view that population limitation will, at some time, be necessary, increased with education. Among those whose family income was at least $10,000 and those whose house-hold head was a professional or business executive, Protestants were more likely than Catholics to view US and world population growth rates as serious and to consider population limitation necessary.

Before World War II, mortality in Australia had decreased progressively since 1860, the first year for which statistics are available. The present study shows that this decline in mortality, although interrupted by the war, continued again during the 1950s but appears to have halted around 1960. In some age groups, death rates have even increased during the 1960s.

The alteration in the trend of mortality has occurred mainly in the middle age group, 35–64, while death rates for persons aged over 64 have tended to remain constant and those for persons aged 15 and under have continued to decline. Death rates for males aged 15–34 declined throughout the period, tending to level off towards the end, whereas the rates for females aged 15–34 have increased during recent years.

The retardation of mortality decline appears to have resulted from a slight increase in death rates from arteriosclerotic and degenerative heart disease, together with rapid increases in death rates from lung cancer for males and motor vehicle accidents for females.

In 1945 Professor Ryle, the first holder of the Chair of Social Medicine at Oxford, initiated a longitudinal study of child growth and development (Ryle, 1945), and in the course of this work various assessments of intelligence were gathered together. The interest of the data lies in the fact that the assessments were made in the same individuals at different times.

An investigation has been undertaken, within the framework of the 1966 national survey, of the knowledge, practice and effectiveness of contraception in Belgium. The basic findings are presented here.

Knowledge of contraceptive methods was rather slight. With the exception of oral contraception, it was the reproductively least effective and sexually most disturbing methods which were best known. Also, the data on the sources of knowledge of contraceptive methods showed a discrepancy between reality and what was considered desirable. Although contraceptive practice was very widespread, a great many of the women questioned felt inhibited about this problem. In general, a restricted number of methods was used and a large majority of the users exclusively practised non-appliance methods. According to shifts in use, a scale of relative acceptability of methods has been prepared.

On the basis of information for a subsample, the majority of the conceptions appeared to be unplanned and this phenomenon increased with parity.

The contraception data have been related to a limited number of sociocultural identification and performance variables, some of which are of considerable sociobiological importance. The relative effect of these variables on contraceptive behaviour has been examined. Interaction between several of them has been demonstrated.

The qualitative analysis of the questionnaires not only allowed answers to be checked and interpreted but also largely confirmed the statistical findings.

The patterns of growth of various components in the populations of selected cohorts in Australia are compared with the corresponding information for selected calendar years. The use of three-dimensional diagrams demonstrates essential differences between the age structures for cohorts and those for the entire population and shows the way in which the two can be related.

This study indicates that tracing of persons through their lifetimes in this way can lead to a greater understanding of trends in calendar year populations, as well as providing a closer link between the historical viewpoint and statistical analysis. This approach is of particular importance in Australia where the pattern and timing of demographic events have produced interesting differences between trends in cohort age structures and calendar year populations.

Analysis of skin pigmentation, by reflectance spectrophotometry at standard wavelengths, of husband/wife pairs of Sikhs living in Britain shows positive correlations between spouses in pigmentation of forehead, but not of inner upper arm. Several possible explanations are considered, the most likely appearing to be positive assortative mating in respect to exposed pigmentation.

There is some evidence, mostly of an epidemiological nature, that coital rates may be positively associated with dizygotic twinning. It is suggested that this link is causal, in which case an explanation becomes available for some curious—and hitherto unexplained—features of dizygotic twinning rates by maternal age and legitimacy.

An analysis of the monthly distribution of births in two areas of Matlab Thana, East Pakistan, indicates that there is a seasonal variation in births different from what would be expected by chance. The highest proportion of births occur in the last three months of a year and the lowest proportion between May and July. Investigation into some of the environmental and social factors which might contribute to the seasonal pattern revealed the following: mean minimum monthly temperature 9 months before birth was inversely related to the number of births; all occupations had seasonal patterns different from what would be expected by chance and the business and mill-and-office occupations had distributions significantly different from each other; the distribution of births for all pregnancy orders was different from chance and the distribution for first order pregnancies was significantly different from those for third and fourth or higher orders.

The familiar and well-established negative association between a woman's age at marriage and family size has received somewhat less attention in recent years. No doubt this is because, with the reduction in fertility of the past century, the observed differentials appear less striking and seem less significant. Age at marriage is a less obvious determinant of family size than in the past. Glass & Grebenik (1954), commenting on the data produced by the 1946 Family Census, emphasized the decreasing importance of the association both absolutely and relatively. Contrasting the completed fertility of the 1900–09 and the 1925 marriage cohorts in Great Britain (Table 1), they argued that, though for all, married women the relative influence of age at marriage was unchanged, the figures for fertile marriages only (those where the wife had at least one child) appeared to indicate ‘that age at marriage and fertility were not quite so tightly linked for the more recent group’. And they added ‘this is the kind of development which would be expected with the increasing spread of family planning’.