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The analysis of fertility in colonizing populations is of great interest, since its individuals experience a major environmental change, and fertility rates can reflect the level of adaptation of the population to its new conditions. Using Northrop's genealogical compilations, this paper examines the fertility pattern of California's early Spanish-Mexican colonists between 1742 and 1876, their fitness levels and their trend across time throughout the colonizing period. A total of 197 women from 599 compiled families who had completed their reproductive period and had at least one child were analysed. The correlations among variables were also analysed in order to infer the relationship between longevity and fertility, and the influence of fertility determinants. The results show a natural fertility pattern, with a very young age at marriage and birth of first child (17.2 and 19.1 years respectively), and also a young age at last childbirth (38.8 years). The population's fitness showed greater values than for contemporary European populations, with 8 of 9.2 children surviving to adulthood, in comparison with 55% of newborns in Finland for the same period, suggesting a good adaptation of the population to their new environmental conditions. No relationship between fertility and lifespan was observed, as has been reported by other authors and in opposition to classical theories. A temporal trend in the number of children, consisting of three different phases, was observed, in accordance with the stability of living conditions in the region.

With an unequalled contraceptive prevalence rate in sub-Saharan Africa, of 43% among currently married women in Zimbabwe, the Central Statistical Office (1989) observed that fertility has declined sharply in recent years. Using data from several surveys on Zimbabwe, especially the birth histories of the Zimbabwe Demographic and Health Survey, this study examines fertility trends in Zimbabwe. The results show that the fertility decline in Zimbabwe is modest and that the decline is concentrated among high order births. Multivariate analysis did not show a statistically significant effect of contraception on fertility, partly because a high proportion of Zimbabwean women in the reproductive age group never use contraception due to prevailing pronatalist attitudes in the country.

Data from the 4172 women aged 15-49 interviewed in the 1988 Vietnamese Demographic and Health Survey were used to examine age at marriage, marriage to first birth intervals and age at first birth. Differences between urban and rural areas, northern and southern provinces and by education of the women were analysed. The majority of the women had their first birth before age 20, but women with secondary education had a significantly higher age at first birth than those with little or no education, and women from the north had a significantly higher age at first birth than women from the south. Rural women and those with little or no education married at significantly younger ages than urban women and those with secondary education; these education effects were confirmed in a rural subsample of women. Women from rural areas and from the north had significantly shorter marriage to first birth intervals than urban women and those from the south, but there were no significant effects related to education.

Indirect techniques are applied to estimate the current level of fertility and mortality among Kuwaiti nationals in Kuwait during 1980–85. The various methods discussed provide estimates in the vicinity of 45 per thousand for birth rate and 8 per thousand for death rate. While child spacing by birth order in Kuwait is about 2 years, the proportion of childlessness is very low (1%). As a consequence of lower mortality and stable high fertility, the Kuwaiti population remains young. [ABSTRACT FROM PUBLISHER]

The article investigates some sources of bias in birth order studies, which may distort the observed distribution of patients by birth-rank. Various biases stemmed when (1) there are biases in the sample due to biases in the population from which the sample is drawn, (2) there is the distortion introduced when sibships are not complete, (3) there are biases which the investigator may introduce in his manipulation of the data and (4) there is the correlation between birth order and the proportion of missing or unreliable information. Practical suggestions for the planning and reporting of birth order studies are presented, and a method is proposed for overcoming the problem of incomplete sibships.

The article examines the birth order and sibship size in a series of over 20,000 psychiatric patients. Results showed that the distribution of birth ranks deviated very significantly from random, there being an over-representation of early ranks in sibships of two and three, and of late ranks in sibships of five and larger. The extent of deviation varied with the year of birth of the patients. Moreover, the type of deviation was in conformity with theoretical prediction and its fluctuations were shown to follow changes in the number of marriages and of births in the population of England and Wales. The practical and theoretical implications of the findings are discussed.