Contraception in women over the age of 40 has received little attention, and accurate data are not readily available. This paper compares data from surveys from the United States and five major countries in Western Europe. Consideration is given to the possible effect on these women of the threat of reduced availability of suitable contraceptive methods as a result of current developments within society at large. This is of particular importance as it appears that, especially in Western Europe, contraception is underutilized in this age group. The benefits and risks of various methods of contraception are discussed. Use of the pill by older women remains controversial. Misconceptions about pill use and the IUD seem to be widespread among women of all ages.

This paper examines the effects of different levels of payment on the acceptance of vasectomy in urban Sri Lanka. Data from 496 vasectomized men are analysed by socioeconomic and demographic characteristics, post-operative problems encountered and attitudes towards vasectomy by amount of payment. The findings show that higher levels of payments have significantly enhanced the adoption of vasectomy, particularly among the low economic status group. The time of vasectomy in relation to the youngest child's age was influenced by the payment scheme. Higher monetary payments have not induced men to become sterilized who would be considered ineligible for the operation. A high level of satisfaction with the decision to have a vasectomy, regardless of payment level, was found. There was no systematic influence of payment levels on post-operative problems.

This paper enquires whether education and age at first birth, both strongly associated with completed fertility, are related to the timing of fertility, in particular the timing of the first three births, among once married white women. Analysis of data from the June 1985 United States Current Population Survey indicates that education is related to the timing of fertility; this relationship has remained relatively constant over time. Age at first birth is associated with the timing of fertility among older but not younger women.

Among a national sample of Canadian women in the Canadian National Fertility Survey of 1984, the excess cumulative fertility of those who started their families early over others has steadily decreased. A difference of approximately two births between early and late starters among older women is reduced to approximately half a child among the younger women. Except for those who start childbearing after age 25, there is little evidence of attempts to catch up after age 30, irrespective of starting age.

Life table analysis is applied to data from the Pakistan Fertility Survey (1975) to examine the effects on birth spacing of a number of socioeconomic variables. Women of more modern backgrounds seem to space their families more closely, but differ little in achieved family size from the more traditional groups. Important factors are age at marriage, age at first birth, province of residence, and whether the woman had ever used contraception. Multivariate analysis taking into account interaction between variables shows that education, urban-rural residence, and province exert independent effects, and so does the cohort of the mother. But the variable with the strongest effect on length of interval, other than that from marriage to first birth, is duration of breast-feeding.

Delivery records from Tanzanian hospitals reveal a marked seasonality of births in areas with holoendemic malaria. Accepted explanations of variations in conception rate are inadequate to account for these seasonal variations. The magnitude of the variation increases with higher parity but it has decreased over the past decade. The differences are related to different activity patterns of younger and older women, and to recent changes in the rural economy. Conception rate has a negative association with rainfall 4 months earlier; birth seasonality is therefore considered in relation to the agricultural cycle. While seasonal variations in sexual activity and pregnancy loss may be contributory factors, female stress due to the combination of malarial infection and physical exhaustion emerges as the major cause of seasonally depressed fecundity in areas with holoendemic malaria.

Longitudinal data were used to examine relationships between sibling variables and adolescents' aspirations at different social status, family environment and ability levels in a sample of 260 Anglo-Australian, 120 Greek, and 90 Southern Italian families. In this follow-up study of an earlier investigation each family had a 16-year-old child and the analyses related to those adolescents. The study suggests that there are different relationships between birth order and educational and occupational aspirations for adolescents from different ethnic groups, even after taking into account the effect on aspirations of measures of ability and family environment.

This paper presents time series data on spouse selection in Canada for the period 1921–78. Homogamous and endogamous trends are examined by age, sex and religion. There is considerable variation in the level of endogamy amongst religious groups. With respect to age, marriages were increasingly homogamous up to 1971 and thereafter less so. Younger males increasingly tended to select brides of their own age group until the 1960s, while older males have been increasingly heterogamous since World War II. Females under 20 years of age tend to select older grooms; other brides show no clear trend in their spouse selection by age.

The family registration records from a village population in a small island of Japan are used to assess the effect of demographic differentiation within a population on genetic measures. When the couples studied are classified by birth cohorts and origins, wives of the couples where one spouse came from elsewhere were older at marriage and had a shorter duration of marriage or registration than wives where both spouses were natives of the village. The mean number of offspring is statistically smaller in the former except for the latest cohort, due mainly to out-migration during the reproductive ages which also resulted in low rates of marriage among the offspring within the village. This leads to a small effective population size and an increased likelihood of genetic drift in the overall population.

A survey of consanguineous marriages in Japan in couples and their parents was conducted in 1983 through questionnaires. The total number of couples studied was 9225; they were chosen from six widely different areas of the country. The kinship coefficient between parents did not decrease with the year of birth. Thus, the recent decline in the frequency of consanguineous marriages in Japan seems to be largely a post-World War II phenomenon. The kinship decreases with marital distance in the parental generation, and socioeconomic class (level of education and occupation) effects are small by comparison with those of the present generation. The rate of consanguinity is significantly higher in the older generation for almost all areas. The kinship between spouses is less than a half of that in parents for the whole of Japan. Geographical variation in the rate of consanguinity is more remarkable in spouses than parental couples.

An analysis of the 1980 Uganda Population Census for South Kampala through indirect techniques provided estimated 1q0 values of 0·0860, 0·0680 and 0·0774 for male infants, female infants and both sexes respectively. The estimated level of 4q1 is 0·0491. The level of adult mortality, especially from age 5 to 19, is lower than infant and child mortality. There is a clear evidence of a sex differential in mortality, males experiencing higher mortality than females. Estimates of expectation of life at birth provided further evidence of sex differences in mortality. The estimated life expectation for males is 54·7 years, for females 59·3 years, and for both sexes 57·0 years.