Birth records in Birmingham were examined for evidence of reproductive compensation following a fetal or infant death. Mothers with a stillbirth, a neonatal death, or a post-neonatal death in 1964 were identified, controls were selected, and subsequent reproductive patterns up to 1969 were compared. There was substantial reproductive compensation following the post-neonatal deaths and a lesser degree after neonatal deaths. Stillbirths were followed by compensation in the first year but this was not maintained and there was a net reduction of effective fertility over the whole 5-year period. Within this pattern, the extent of compensation varied according to the number of older surviving children. Both fetal and neonatal deaths tended to recur. There is evidence that reproductive compensation is partly attributable to pre-existing fertility differentials, but also to eventdetermined modifications of reproductive behaviour. With respect to haemolytic disease of the newborn the data provide some evidence in support of the theory that gene frequency stability depends upon reproductive compensation, but the interpretation of the data in this respect is not completely reliable.

In this paper, non-marital pregnancies are defined as the sum of ex-nuptial confinements and the first nuptial confinements delivered within the first 8 months of marriage. Analysis is based on the annual statistics of live births, marriages and female non-married population as enumerated in the 1947–71 censuses. The incidence of non-marital pregnancies increased significantly in Australia between 1947 and 1971. This was found to be mainly due to rising ex-nuptial fertility rates, and, to a much lesser extent, to increased frequency of pre-marital pregnancies. A lesser proportion of pregnant non-married women were married before delivery in 1971 than in 1947. Some of the social implications are discussed.

This paper attempts to assess, by assuming the sex of a live birth to be a binomial event, the contribution of desires for specific sex compositions to the level of birth rate. Data from India are utilized to quantify the contribution. It is found that the birth rate in India could be greatly reduced by an effective campaign of limiting family size to three, even if the campaign were accepted by only those couples who had achieved their desired family composition.

Data published annually by the Registrar General for England and Wales indicate that over the past 10 years the numbers of births—and, since 1968, of legal therapeutic abortions—to teenagers have increased substantially. During much of the same period the fertility of older women declined. This paper examines the recent demographic trends in teenage pregnancy, and compares the fertility of these teenagers with that of older women.

The influence of the country of origin of the father on mean birth weight of offspring of Jewish immigrants to Israel has been examined in an analysis of 98% of records of live births for the period 1968–70. The mean birth weight of infants born to parents from the same country (in-group marriages) was 3309 ± 570 g and that of infants whose parents came from different countries (out-group marriages) was 3289 ± 565 g: these differences are not significant.

Infants born to immigrants from North African countries are heavier, and those born to immigrants from Asian countries lighter, than the Israeli mean. Apart from Algeria (whose immigrants have babies heavier than those from other North African countries) and India and Yemen (whose immigrants have babies lighter than those from other countries of Asia) there were no significant differences in adjusted mean birth weight by country of origin, within each continental group.

Mean birth weight is determined by a combination of maternal and environmental factors, paternal factors having little effect.

Analysis of birth weights of second and subsequent generations of Israeli-born, by origin of their grandparents, shows a fall in mean birth weight of those of North African descent and a rise in those of Asian descent, i.e. a tendency to approach an Israeli mean.

(Summary in Hebrew, p. 164.)

It is argued that the author's hypothesis relating timing of insemination (and hence coital rate) to the sex ratio of the resulting children is supported by the available data on the variation of sex ratio with (1) sibship size, (2) the presence of twin sibs, and (3) parental adherence to the Jewish faith.

An attempt has been made to determine which of several social, demographic and economic variables best account for the variance in contraceptive use in a low-income, urban Colombian population. The results indicated that of the independent variables included, occurrence or non-occurrence of intercourse in the past month, education, employment status, marital status and age were the best predictors, in that order. Altogether these factors accounted for 17% of the variance in contraceptive use and 87% of the variance within the model. The remaining variables had relatively little predictive utility; and this was particularly true for interspousal communication, race and religious commitment.