An attempt was made to predict alcohol use among 101 American white boys aged 13–16. The model combined genetic and social variables. The analysis revealed evidence of a genotype–environment interaction and thus the use of either the biological or social variables alone poorly predicts alcohol use.

This paper examines the relationship between parental education and child mortality in Burundi using data collected in the 1987 Demographic and Health Survey. Proportional hazards models are estimated to examine this relationship, while holding constant other known child mortality determinants. Parental education proves to be a key factor in explaining differences in child mortality, the effect of maternal education being particularly strong compared to paternal education.

The Italo-Greek ethnolinguistic minority, living in thirteen villages of southern Italy, marry largely amongst themselves but there are some intermarriages with native Italians. The majority of marriages are within the villages, but there is some marriage movement from one Italo-Greek village to another. Data on marriage and birthplace of parents and grandparents obtained by questionnaires to families of primary school children (aged 6–13 years) are analysed, to show the trends in breakdown of isolation over the last two generations.

The nursing behaviour of rural Nepali women, from two castes inhabiting the same village, is quantified on the basis of 2202 hr of continuous and direct day-time observation over 1 year. Feed duration, interval, total time and daily frequency are examined in relation to women's work, particularly the type of subsistence activity and seasonality. ‘Opportunity’ feeds are governed both by infant demands and maternal activity. Caste differences in birth intervals are also discussed.

Levels and trends of fertility in the Arsi and Shoa regions of Central Ethiopia are examined, using data from the 1986 Population, Health and Nutrition baseline survey of the Ministry of Health of Ethiopia. The population has high fertility. Total fertility of six children per woman in the late 1960s increased to eight children per woman in the early 1980s, then declined to seven children per woman in the mid-1980s. Urban fertility declined by a substantial amount during the 15 years before the survey while rural fertility increased during the same period.

The implications of high fertility are considered.

Using data from the 1984 Canadian Fertility Survey, proportional hazards modelling was employed to determine factors associated with the likelihood of voluntary sterilisation among 5315 women of childbearing age, and the trends in timing and differences in the likelihood associated with different age cohorts. Multivariate analysis suggests that educational attainment, parity and duration since last birth at the time of sterilisation, religious commitment, province of residence and marital status at the time of sterilisation, are all important predictors. Education and parity attainment emerged as the best predictors of the timing of voluntary sterilisation in all age cohorts, but the contribution of other covariates varies between cohorts.

Birth localities of spouses from two generations are examined, to assess the extent to which the observed patterns of marital mobility link the spatially separated and kin-structured sub-populations within the ‘shahrestan’ of Nowshahr. The results indicate localised marriages and short range movements from the village of birth in both generations. Temporal increase in the range of movement indicates the breaking down of isolation, thus providing greater possibilities for admixture and genetic homogeneity.

A significant increase occurred in the initiation and duration of breast-feeding among Honduran women between 1981 and 1987. Changes in population characteristics (e.g. level of education of women) would be expected to lead to a decrease in breast-feeding at each infant age, but these were offset by behavioural changes that led to an increase in the likelihood of initiation and continuation of breast-feeding. An exploration of relevant factors suggests that the PROALMA breast-feeding promotion programme has had a profound effect on the breast-feeding behaviour of Honduran mothers.

Analyses of the height variation of 16-year-old members of the British National Child Development Study revealed a number of biological and social variables which associated with stature. After multiple regression analyses only eight variables, namely social class, family size, tenure (owner occupied or one of several types of rented home), crowding status, number of children sleeping in the bed, region of the country, sex of child, and pubic hair rating, remained significant. The total variation explained by these biosocial variables was 37·5%.

Although demographic information on Nigeria has increased in the past two decades, information on adult mortality in the country is still sparse. This paper provides information on the levels and trends in male and female adult mortality among the Kanuri of north-east Nigeria. Analysis of reports of orphanhood and widowhood suggests moderately high levels of mortality.

Official statistics on abortion in South Australia for the period 1971–86 are analysed in terms of incidence, age of patients and nuptiality, reasons for abortion, method of termination, period of gestation, previous abortions and concurrent sterilisation. Demographic implications are discussed and recommendations are made for more education and counselling, especially for younger and unmarried women for whom the incidence of abortion seems to be rising.

The method of isonymy to estimate inbreeding is applied to the historical population of the Quebrada de Humahuaca (Province de Jujuy, Republic of Argentina). Data from the baptismal records of the Parochial Church of Humahuaca from 1734 to 1810 were grouped into two periods, 1734–72 and 1773–1810. The analysis was carried out twice: (a) using the surnames exactly as they were registered; (b) combining homonymous surnames which were pronounced or spelt in a similar way. The random and non-random components of inbreeding have been investigated through different methods. There were no significant differences between the results of the two analyses, nor between the expected and observed isonymy. The value of Flies somewhere between those for offspring of first cousins once removed and second cousins once removed. There is a tendency for F and its components to increase through time. It is concluded that the high altitude aboriginal population of Humahuaca Parish must have behaved as a panmictic unit.

Age at marriage is one of the factors that influence the fertility behaviour of women, particularly in a society like Nepal where contraceptive use is low. Socioeconomic and cultural factors, particularly religion and ethnicity, are important variables in determining age at marriage in Nepal. Fertility was negatively related with age at marriage. Marriage duration had a greater influence on fertility than age at marriage, although these were strongly correlated.

Japanese and British 9-year-old children were compared on the standard progressive matrices and twelve reaction time parameters providing measures of simple and complex decision times, movement times and variabilities. The mean of the Japanese children on the progressive matrices exceeded that of the British children by 0·65 SD units and on the decision times component of reaction times by 0·50 SD units, suggesting that the high Japanese mean on psychometric intelligence is largely explicable in terms of the more efficient processing of information at the neurological level. Japanese children also showed faster movement times but, contrary to expectation, had greater variabilities than British children.

On a sample of some 2000 children living in two ecologically different zones (the Wooded and Guinea savanna) in Kwara state, Nigeria, body measurements were taken, to serve as indicators of the state of nutrition. There was more undernutrition in the Guinea savanna than in the Wooded. More males than females were undernourished in the Guinea savanna but not in the Wooded. It is argued that the differences between districts stem from social and cultural variables.

Information on social and family aspects of marriage was obtained from a sample of over a thousand marriages solemnised in England and Wales in 1979. The data include the standard demographic variables concerning the couple and their marriage and also: the day of the week the marriage was celebrated; whether the fathers or relatives of similar surname to the spouses acted as witnesses; the patterns of name usage by brides; the numbers of forenames of the marriage partners and their fathers; and the frequency of bridegrooms having one or more forenames in common with their fathers. The factors are analysed in terms of social class differences as well as in relation to the distance over which marriages range and other demographic characteristics of the partners and their marriage.

Social and biological factors influencing birthweight of 3053 Ilorin babies were studied. The mean birth weights were 2·998 kg ±0·133 (SD) for males and 2·932 kg ± 0.154 (SD) for females. Multiple regression analysis showed that maternal weight, height, age, education and ethnicity, and child's sex, significantly affected birthweight of infants. Some quadratic and interaction terms also contributed significantly to the prediction of birthweight. The strategies to control the incidence of low birth weight are discussed.

The 1975–76 Bangladesh Fertility Survey data show little evidence that breast-feeding is the intermediate factor through which birth intervals influence child survival in Bangladesh. Preceding birth interval, subsequent pregnancy and breast-feeding duration each have an independent influence on early mortality risk. Within a specific interval the risk of dying decreases with increase in duration of breast-feeding, and also with an increase in the time between the index birth and the next pregnancy. The death of the immediately preceding child in infancy has a significant negative effect on the survival chance of the index child at ages 1–5 months. However, death of the preceding child appears to have a significantly positive effect on the survival chance of the index child between ages 9 months and 5 years; this may be related to competition between siblings.