This paper explores factors affecting the fertility of islanders off the north coast of Sri Lanka, the centre of concentration of the Sri Lanka Tamils. The variables contributing most to the fertility variation among Grama Sevaka divisions, are the proportions of elderly in the population, of females employed to total employed, and of females aged 5–14 attending school. Overall, however, only 43% of the total fertility variation is explained, considerably less than in other Sri Lanka areas studied.

Medical students and members of infertile couples were questioned about their knowledge and attitudes toward artificial insemination using donor semen (AID). While both groups were well-informed about AID, considerable attitudinal diversity existed. Subjects generally favoured AID for infertile couples, for single women and for situations where the risk of inheritable retardation or genetic disease existed. Members of infertile couples were more positive about AID than were medical students, and females were more positive than males. The results indicate continued controversy regarding several aspects of AID such as whether to permit AID recipients to select their own donor and whether children conceived through AID should be so informed. The implications for infertility counselling are discussed.

The main aim of this paper (see Author's note) is to demonstrate that definitions of which groups of people constitute indigenous minorities are subject to change—changes which are often due not so much to our increasing scientific or academic knowledge about particular groups of people, but to political factors. A secondary aim is to document two cases which have so far found little or no mention in the literature, one drawn from Zimbabwe and the other from Australia.

The natural region of the Jara, with an area of 2500 km2 occupies much of the south west of the province of Toledo, and extends into the provinces of Caceres and Ciudad Real. It is situated between the Tajo and Guadiana rivers, south of the town of Talavera de la Reina, the centre of the economic life in this region. Its highlands are covered with xerophytic vegetation, of which the most common plant is the jara (Cistus ladaniferus), from which this zone takes it name, (Fig. 1). It has been occupied from the neolithic period onwards by peoples of different origins, e.g. Romans, Muslims, Jews, Mozarabs (Jimenez de Gregorio, 1959) but the present population derives from settlement from the north of the Tajo river beginning in the 14th century following the upheavals of the Moslem–Christian wars.

A new approach is suggested for assessing the relationship between birth order and pregnancy risk. Population data are used to estimate the risk of a poor pregnancy outcome after different reproductive histories. The risk of a poor outcome at the first pregnancy appears to be twice that at subsequent pregnancies, but no change in risk is observed between the second and fifth birth orders. If there has been a previous poor pregnancy outcome, the risk of another is increased four-fold.

Using daily report data from 85 husbands and wives for about 100 days each, this paper explores differences in sexual behaviour between menstrual and non-menstrual days. Intercourse and orgasm are reduced during menstruation, in association with impressively less female desire for intercourse during menstruation. In the highly educated group studied, the women respond to a resultant potential increase in male sexual frustration by providing the husbands an increase in non-coital orgasm on menstrual days.

The influence of fertility preferences on contraceptive use is examined among a sample of low income, rural Egyptian women. The findings reveal that while overall use of contraceptives was at modest levels, one-third of respondents who wanted no more children were currently practising contraception. Moreover, fertility preference emerged as the strongest predictor of contraception among the series of social and demographic factors examined.

In the absence of reliable fertility statistics in the Sudan, estimates are based on census or sample survey data. Methods of analysis are applied which are suitable to the kind and quality of the collected information. This paper uses data provided by the World Fertility Survey of the Sudan. The number of children ever born tabulated by the duration of marriage is used to derive an estimate of the age pattern of fertility. The level of natural fertility is found to be low. However, the calculated crude birth rate is high and consistent with rates calculated by other methods using different data.

This paper examines rates of marital childlessness in the developing countries of the world and separates them into voluntary, involuntary and related components through a decision-tree model based on fecundity, contraceptive behaviour, pregnancy status, age, years married, and other variables. The principal data are taken from World Fertility Surveys. The conclusion is reached that virtually all of the permanent childlessness in the developing countries examined is involuntary.

Cultural—‘ethnic’—differences within national populations have recently become the focus of considerable academic and political debate. This paper considers their demographic significance and reviews some facts and theories on the demography of minorities.

It cannot present a comprehensive theory of the demography of ethnic minorities. Such a theory must be part of a more general analysis of cultural effects on demographic variables—which so far is lacking in demography. Neither can it review exhaustively the facts of minority demography; they are not collected or made available in sufficient detail from many countries with minority or multiple nationalities. The aims of the paper are accordingly less ambitious: to consider the political and academic import of minority demographic differences, formulate questions that might usefully be asked about them, and present a few examples in detail.

It is generally thought that birthweight varies with the sex of the infant, gestational age and parity; there is, however, some controversy as to whether birthweight increases monotonically with parity. Further, some have suggested that maternal height and social class are also important, whilst earlier authors stressed the importance of genetic factors. This paper re-examines these relationships on the basis of an analysis of data on 6472 women who had a sequence of two or more singleton live births. The analysis shows first that the raw birthweights increase up to the fourth birth and that there are strong correlations between successive birthweights. However, when the birthweights are standardized for gestational age, maternal height, parity and sex, the relation between birthweight and parity almost disappears. On the other hand, the correlations between successive birthweights remain among the standardized scores, suggesting that there are other features specific to the mother which affect birthweight.

The present paper is based on data from the Nepal Fertility Survey 1976 and examines the fertility differentials in Nepal by socioeconomic variables. Of all the variables examined in this study marital duration is found to have the greatest impact on fertility. With standardization for marital duration, women in the mountains have a lower number of children ever-born than women in the hills and terai. Education of husbands rather than wives seems to affect fertility in Nepal.

Major findings from an analysis of demographic information collected in a 1979 survey in the Yemen Arab Republic (North Yemen) are that: levels of contraceptive use are extremely low in the rural areas that constitute most of the nation and considerably higher in the capital, Sana'a; fertility is very high and, until recently, was higher in Sana'a than in rural areas; mortality of children is very high with small urban–rural differentials; breast-feeding durations tend to be short, considering Yemen's extremely low level of development; and, female infants appear to be breast-fed longer than male infants in Sana'a, a phenomenon never previously documented. It is argued that the observed convergence between fertility levels in Sana'a and rural Yemen results from increased contraception in Sana'a, which offsets fertility differences introduced by longer breast-feeding in rural areas.

This paper analyses the influence of maternal factors (mother's age, parity, prior birth interval, and subsequent birth interval) on mortality risk for 2150 Bangladeshi infants and children, taking the sex and age of the child into account. Logistic regression estimates from retrospective maternal birth histories for the period 1966–75 reveal age and sex patterns consistent with previous research. These estimates also demonstrate that there are associations with mother's age and parity, but that prior birth interval emerges as the strongest predictor of mortality risk. It appears that part of the mortality risk of mother's age and parity actually stems from association with shorter prior birth interval, a factor to which infant and child health programmes need to give more attention.

Cross-sectional and longitudinal study of a large sample confirms that mean marital coital rates decline very rapidly over the first year of marriage. They seem to halve over the first year of marriage, and then they take perhaps another 20 years to halve again. This pattern of decline is interpreted as evidence against the suggestion that coital rates are closely related to female hormone levels.

The higher correlation of marital coital rates with wife's age than with husband's age, it is argued here, is because wife's age is more closely associated than husband's age with duration of marriage (here seen as the most important of these three variables in the determination of coital rates). This is because of the substantially smaller variance of wife's age at marriage than husband's age at marriage.

The title of this paper suggests at least two possible points of departure. First, one can argue that spatial patterns are themselves an important feature in the study of social life which deserves our attention: that there is a significant geographical dimension to social interaction. Secondly, the title also implies that various social groups interact differentially with one another: that interaction is itself a proper focus for social investigation. Both points will be developed in the present paper with respect to ethnic minorities in Britain and the United States.

The records of 15 years of paediatric necropsies in the Department of Pathology of the Hospital San Ignacio in Bogota were reviewed and the results classified according to the various types of genetic pathology. It is shown that out of 1463 paediatric necropsies, 377 (25·8%) had either a congenital defect or a disease considered as genetic to some extent. Simple Mendelian diseases and chromosomal disorders account together for more than 5% of the total deaths. When the pathologies with a complex genetic contribution to the aetiology are also taken into account, the figure rises to more than 20%. Overall, the study shows that the burden of genetic pathology is also important in countries, like Colombia, where other causes of death have traditionally been the main concern of public health measures.

The patterns of male social mobility among the contemporary populations of Otmoor are described in terms of both intra- and inter-generational mobility. The social classes are differentiated by IQ and it is shown that sons' IQ is more highly correlated with their class, after their social mobility than before it. In 85 father-son pairs the number of steps sons moved in the social scale is positively related to the magnitude of the difference between their IQ and that of their fathers. However, the relationship between social mobility and IQ appears to be entirely confined to non-locally born subjects and the social mobility among the locals, although of comparable dimension is essentially non-meritocratic. These findings are discussed in relation to the structure of the Otmoor populations and particularly the phenomenon of selective out-migration.

The paper uses multiple regression analysis to examine the variation in fertility among Indian Tamil concentrations in the Grama Sevaka divisions of Sri Lanka. Significant contributions are made by the proportion of females employed in agriculture, and the proportion of females aged 5–14 attending school, which together account for 85% of the variability. These variables serve as an index to the underlying attitudes to fertility and reproductive behaviour.