To explore the relation between arrays of multiple genetic systems and the age structure of a population, twelve plasma and red blood-cell polymorphisms were considered in combination. A comparison of observed and expected numbers of persons sharing an array indicated that 72·1% of arrays were in excess of expectation, largely due to association between over-representation and simple heterozygosity score. There was evidence of association between heterozygote excess and age, the proportion of over-represented arrays falling with increase in age. Some implications of this result are discussed.

Data from a survey of 1699 currently (once) married males are used in examining ideal family size in Northern Ireland, an area where fertility remains quite high by west European standards. Although there are several problems concerning the measurement and use of ideal family size, an analysis of the Northern Irish data indicates that the responses appear to be valid. For example, most respondents can formulate an ideal family size in numerical terms, there is a considerable degree of variation in the responses and these are not necessarily a function of actual family size. Northern Irish family size ideals (mean 3·6) are considerably greater than those of many west European countries and these ideals also vary within Northern Ireland. Religious grouping proves to be the major factor influencing these variations, with Roman Catholics generally expressing an ideal (mean 4·4) for large families. However, other factors are also associated with variations in ideal family size and the paper considers the roles played by education, age, occupation, region of residence and religiosity. Also, ideal family size does not always correspond with actual family size, indicating that while some married men possess relatively large family size ideals but have smaller families, others have large families but favour more moderately sized ideals. It is evident that attitudes to fertility in Northern Ireland are in a state of change. The value of ideal family size data in understanding fertility patterns is emphasized.

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.

From matched birth and census records in the Matlab area of Bangladesh, monthly fertility rates for the period 1970–74 are studied for seasonal patterns by age and parity. Trigonometric regression techniques are used to summarize and compare the multiple series. Pronounced seasonal patterns are apparent for all age and parity groups. The general fertility rate peaks in December with a seasonal variation of 42% above and below the mean level. For younger women at low parities the peak is in late October, while for older women of higher parity it is in January. The shift progresses linearly with age and parity though the age effect is the more pronounced. A seasonal pattern of fecundability which varies by age group could explain the shift.

A psychological measurement technique, the semantic differential, is used as a measure of the perceptions of contraceptive methods among 172 sexually experienced undergraduates. This technique enables the calculation of an acceptability score based on subjectively defined attributes. Factor analysis of the ratings identifies seven major dimensions, which have to do with effectiveness, discretion, pleasure, legality, permanence, harmfulness, and cost. A sex difference is found in that comfort and mood factors are more salient to females than to males.

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.

Estimates from archaeological data of the numbers in the elite classes, non-elite occupational specialists, density of population, city size, and size of political units in the ancient Maya civilization suggest that there was a quantum shift in rate of development in the Early Classic period, associated with intensification of agriculture, and that the social structure approximated to a generalized feudal pattern.

This paper extends the analysis of sibling groups from Ghana (Goody et al., 1981) by a comparison with seven sets of data from various parts of the world. Sex preference is analysed from the actual holdings of children, taking into account the numbers and sequence of sexes by which the family is built up. The hypothesis examined is that sex preferences are related to general socioeconomic factors and in particular to differences between extensive and intensive systems of primary production. The results suggest that such preferences are shown in the holdings of completed families, though their effects are of small magnitude and they vary from society to society.

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.

In a wide-ranging survey, ways are examined in which human personalities can be categorized and the relevance of these categories to sporting performance is examined. The profiles produced by studies of the Eysenck and Cattell type, the significance of the ‘trait’ and the ‘interactional’ approaches and the correlation of personalities with physical performance are considered. The importance of such factors as achievement motivation, causal attribution, selfefficacy, mental rehearsal and concentration is examined. Consideration is given to the role of sport in the fulfilment of the personality.

From a longitudinal study over 25 years (1951–75) of two adjacent Gambian villages, the data allow estimates of population growth, birth rates, age-specific mortality, female fertility, and infertility rates in the two sexes. Such intensive but small scale local inquiries provide valuable information on topics not covered in official published statistics, and also data from which the reliability of some census details can be estimated. There are many similarities but also differences between the two villages. Population growth rate was 1·1% per annum for Keneba and 2·2% for Manduar. Crude death rates averaged 36·7 per thousand for Keneba and 24·7 for Manduar and showed little difference between the sexes. For Keneba and Manduar respectively stillbirth rates were 63·9 and 88·6, first week mortality 49·2 and 44·9 and neonatal mortality 85·2 and 49·6 per thousand live births. In Keneba, where survival to age 5 years averaged 50%, young child mortality was significantly higher than in Manduar but mortality at older ages was not. Season profoundly affected child mortality: about 45% of all deaths under 15 years occurred in the late wet season, August–October. Maternal mortality in Keneba was 10·5 and in Manduar 9·5 per thousand. Crude birth rates averaged 58·4 per thousand for Keneba and 49·0 for Manduar, rates per thousand women aged 15·44 years averaging 248·5 and 215·3 respectively.

In both villages mean birth interval increased progressively with the survival of the preceding child. In Keneba the interval increased from about 16 months when the first of the two children was stillborn to nearly 37 months when the first child survived to 2 years. In Manduar the corresponding values were 19 and 36 months. Analyses of obstetric histories indicated that total fertility was of the order of 7·5 live births per woman in Keneba and 6·4 in Manduar. Estimates of primary infertility for females were 3·6% in Keneba and 5·6% in Manduar, and for males 3·1% and 1·9%. Estimates of secondary infertility in females were 13% in Keneba and 19% in Manduar.

Using data collected through follow-up home visits to a sample of mothers, whose singleton babies were born at the Dufferin Hospital, Lucknow, September 1976—August 1977, estimates are made of infant mortality in Lucknow city, and its differentials by socioeconomic, demographic and health care characteristics of the infants and their families. Infant mortality was 74·5 per 1000 births during the year 1976–77 and there is evidence of some recent decline in it.

Among socioeconomic factors considered, infant mortality is found to be inversely related with caste status among Hindus, education of mother, father's monthly income, and father's occupation. Infant mortality exhibits a J-shaped distribution in relation to maternal age and parity and a reversed J-shaped distribution in relation to maternal age at marriage. Among health and health care factors, antenatal care of the mother appears to exercise a negative influence on infant mortality, which also shows a marked negative relationship with birth weight and feeding index of the child. The findings suggest important policy implications, which, if followed, would help to reduce infant mortality, and would thus remove a serious obstacle in the way of acceptance of the small family norm and its achievement through the adoption of family planning.

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.

The HRR test was used to study the frequency of colour vision defects in 297 Zulu men and 43 Zulu women of Natal, two Basuto men in Natal, and two Swazi men and 21 Swazi women in the Transvaal.

The frequencies agree with the work of other authors, that the numbers of red–green defectives in the black populations of Africa are less than half those among European whites. The observed frequency of women defectives is greater than that expected from the number of males, and the difference is probably due largely to the inclusion of a small number of women with considerable heterozygous manifestation.

No yellow–blue deficient subjects were found.

The results of a demographic study of two occupationally distinguishable caste communities inhabiting the neighbouring settlements of Balaramchak and Bamanchak in the Geonkhali region, coastal Midnapore district, West Bengal, are reported. Although there is no significant difference in mortality between the two settlements, fertility is generally higher in Balaramchak than in Bamanchak. Further, fertility seems to have declined over time in both the settlements, with the decline commencing earlier in Bamanchak. Possible explanations for the inter-settlement and temporal differences in terms of occupation and family planning practices, as well as the possible genetic consequences of these differences, are discussed.