Atoll-dwelling people of Tokelau in the central Pacific have been studied in their home environment and after migration to the industrial culture of New Zealand (NZ). The NZ migrants reflect the predominantly male and young composition of the migrating group. Recent migration has eased the lot of the surplus young women from Tokelau, resulting in earlier marriage and less long-term spinsterhood. The apparently higher fertility of women residing in NZ is largely explained by selection of female migrants who already have two or more children. Earlier menarche and earlier marriage in NZ probably contribute little. Future trends will be monitored, and a decline in migrant fertility is expected, if Tokelauans follow the pattern of other Polynesian migrants to urban environments.

Data from 375 Ethiopian mothers show lactations of between 25 and 30 months in the majority, very prolonged even by African standards. Maternal nutritional status, as shown by body weights, was low due to very low food energy intakes. With frequent suckling already raising prolactin levels, these very low energy intakes may also result in yet more prolactin secretion. New pregnancies are delayed and birth intervals extended beyond normal African standards by all these factors.

Over the course of a year, 162 women requesting termination of pregnancy were assessed by interview by both a consultant gynaecologist and a medical social worker. Only thirteen (8%) were referred as requiring medical advice and most of these basically had social problems. In contrast, 85 (52%) were found to require the help of the medical social worker for either detailed counselling or various supportive measures.

The fifty states of the US were compared in 1971–72 and 1974–75 with respect to percentage apparent conceptions aborted and infant mortality rates attributed to various causes. Only non-vehicle accidental deaths were consistently related to abortion. The correlation is non-linear; non-vehicle accidental deaths were especially high in states with little or no abortion. A decline in non-vehicle accidental deaths from before to after the Supreme Court decision was most pronounced in states where there were fewest abortions before the decision and where increases in abortion occurred following the decision.

This study examines by multiple regression analysis the factors influencing district variation in infant mortality rate in Sri Lanka in a given year (1971). It shows that 83% of the district variation is explained by differences in the proportion of the population that is Indian Tamil, the proportion of female employees, and the proportion of females aged 15–19 with at least 5 years of education.

In a retrospective study, the impact of breast-feeding on the survival probabilities of children born to women in hospitals in Cairo, Egypt, is estimated. The analysis shows that early cessation of breastfeeding is associated with higher mortality and the effects are more severe the lower the education level of the mother.

Evidence from a national sample of New Zealand adults demonstrates a high prevalence of obesity, including severe obesity. Maori subcutaneous fat distribution is different from white, the former having relatively greater subscapular than triceps skinfolds compared to whites. Obesity is more prevalent in Maori. In whites, higher educational attainment tends to be associated with lesser indices of obesity and greater stature. The obese do not appear to have greater dietary energy intakes, but are less likely to consume breakfast than the non-obese.

The relationship between anthropometrics and three measures of Darwinian fitness—number of surviving children, number of living siblings and marital status—was sought in a population practising no contraception. The pattern suggestive of stabilizing selection was evident for one dimension, destabilizing selection for another dimension, and directional selection for yet another. The dimensions studied were those least intercorrelated one with another. Stabilizing selection for human physical characteristics may not be a universal phenomenon.

Genetic structure of the Cumbrian population is examined from data on gene and genotype frequency distributions, on geographical location, and on population movement in two generations.

The population is genetically heterogeneous; the central Lake District particularly, and also Carlisle and the southern periphery, stand out as distinct from the remainder and from each other. Regional subdivision of the population is sufficient to lead to some increased overall homozygosity, but its effect on inbreeding is considerably lower than the inbreeding level within regions, the latter being highest in the Lake District and the southern periphery. Examination of isolation by distance shows distance to be an important determinant of genetic differentiation in Cumbria; local and regional kinship levels are similar to those in alpine Swiss areas. Migration analysis suggests the distinctness of the west coast and southern periphery, and a slight increase in kinship between regions in the last generation.

The measures of genetic distance are closely correlated with each other. The measures of kinship derived from migration frequencies between regions are highly correlated with each other, and with geographical distance, but not with genetic distance. Present migration patterns are insufficient to account for the affinities within and between regions indicated by the genetic variation. It is possible that retention of Norwegian influence over a great length of time in the central Lake District is a major contributory element in present-day genetic heterogeneity in Cumbria.

Reproductive performance of the human female is simulated by Monte Carlo methods. The results clearly suggest the operation of natural selection on the length of the female menstrual cycle, brought about by differential fertility. It is argued that the selection pressure towards a shorter cycle, with a selective advantage of approximately 1% per day of shortening, is balanced by internal physiological determinants preventing excessive shortening, so the result is a situation of stabilizing natural selection.

Demographic and socioeconomic data were collected from the Hindu, Mahishya caste community of Chakpota village, Amta Police Station area, Howrah district, West Bengal, to examine the possible effects of economic differences on fertility and mortality, and their potential genetic consequences. The age structure of the low, medium and high economic groups suggests decreasing growth potentials from the former to the latter, with a recent decline of fertility in all the three groups. Analogously, a trend of fertility and mortality decline from the low to high economic groups seems to exist, although with some exceptions. The index of total selection intensity (I) is the highest in the low economic group. Genetic selection seems to be sensitive even to very small differences in economic condition, among related subpopulations of the same population, sharing very similar physical environmental stresses.

The apparently closed societies of the New Guinea Highlands were traditionally in possession of quite large quantities of pearl shells traded from the coast. Since these constituted almost the only category of goods not produced as easily in the Highlands as the lowlands, and since they formed an appreciable component of the bride wealth, they suggest directional mating leading to an outward movement of women from the Highlands. Marriage movement in three samples of women confirms this suggestion.