Polygyny and fertility differentials among the Yoruba of western Nigeria

Data are analysed from the 1973 surveys of the Nigerian segment of the Changing African Family (CAFN) Project, which covered Yoruba women and men in Ibadan and the Western State of Nigeria. Of the 5874 women who were in union during the CAFN 1 survey, 54% reported that their husband had only 1 wife and 46% that their husband had more than 1 wife. Of the 1234 women in unions in the CAFN 2 survey, 49% reported monogamous husbands and 51% polygynous husbands. Differentials in fertility levels between women in monogamous unions and those in polygynous ones are investigated using mean number of children ever born as the measure of fertility. Factors examined include proportion of childless and infertile women, frequency of intercourse, age, educational level, religion, marital mobility (divorce) rank of wife and sexual abstinence. The CAFN 1 survey shows that wives of polygynists tend to be older than those of monogamists. Because of this the reported mean number of children ever born was higher for the wives of polygynists than for the wives of monogamists. When the data are standardized for the difference in age, the fertility levels of the women in the 2 types of unions were much closer to each other. When religion, education, abstinence, and occupation are also taken into account, it is observed that the 2 groups of women have similar levels of fertility. A multiple classification analysis was performed using number of wives of husband, educational level, religion and father's occupation as variables and occupation of spouse, place of birth, length of abstinence, contraceptive practice and age as covariates. The result also shows that the number of wives of the husband does not significantly affect the fertility level of women when other factors are taken into account. A high proportion of the Yoruba women are in polygynous unions and most of those in monogamous unions are potential wives of polygynists. Because of this, and particularly because most women try to have as many children as they can, the women in the 2 types of unions experience similar levels of fertility.     

Gender relations: husband-wife fertility and family planning decisions in Kenya

Although Kenya's fertility rate has declined from 6.7 births per woman in the mid-1980s to 5.4 births per woman in 1993 (NCPD, 1994), population growth is still high, yielding a doubling time of 35 years. This study uses the 1993 Kenya Demographic Health Survey data collected from 1257 couples to examine the socioeconomic and sociodemographic characteristics of married men and women and their communication with their spouses over fertility and family planning decision-making practices. The logistic regression analysis shows that education for both men and women, discussion of fertility and family planning between spouses, male approval of use of contraception and male family size desires are important factors that influence ever-use of family planning.     

Proximate determinants of fertility in Nigeria

Data from the 1981-82 Nigeria Fertility Survey (NFS) are used to identify the key proximate determinants of fertility in Nigeria. The patterns of their individual and collective effects are analyzed in a search for possible sources of fertility change. Exposure to the risk of childbearing through first marriage is found to be the most important proximate determinant of Nigerian fertility. Subsequent to marriage, fertility is determined mainly by breastfeeding and postpartum sexual abstinence. Where fertility shows significant socioeconomic variations, there are equally identifiable patterns of the impact of the proximate determinants which explain these differentials to a large extent. On a national scale, the observed patterns of the impact of the measured proximate determinants do not appear to suggest that Nigerian fertility is soon to experience a large decline.     

Factors affecting ever-married men's contraceptive knowledge and use in Nigeria

African men play important roles in the decisions about family life, including fertility and family planning. However, fertility and family planning research and programmes have ignored their roles in the past, focusing only on women's behaviours. Since the 1994 International Conference on Population and Development (ICPD), interest in men's involvement in reproductive health has increased. Unfortunately, data on their knowledge and use of contraception are generally scanty. This paper examines knowledge and use of contraception among ever-married men in Nigeria. A total of 1451 ever-married men aged 18-55 were interviewed in Imo and Ondo States, Nigeria. The findings reveal that men's level of contraceptive knowledge is high in the study areas. About 90% knew at least one method of family planning. Furthermore, the level of contraceptive use among married men is such that men could participate in family planning activities if there were adequate programmes to involve them. Men in the sample areas were found not only to support their spouses' use of contraceptives, but were actually using condoms to delay or prevent pregnancy. Age, education, place of residence, number of living children and being counselled for family planning were identified as key factors determining contraceptive knowledge and use among married men in the study areas. To ensure increased participation of men in family planning, programmes must be designed to educate them on the need for family size limitation and involve them in service delivery, even if only to their male counterparts.     

The coevolution of human fertility and wealth inheritance strategies.

Life history theory concerns the scheduling of births and the level of parental investment in each offspring. In most human societies the inheritance of wealth is an important part of parental investment. Patterns of wealth inheritance and other reproductive decisions, such as family size, would be expected to influence each other. Here I present an adaptive model of human reproductive decision-making, using a state-dependent dynamic model. Two decisions made by parents are considered: when to have another baby, and thus the pattern of reproduction through life; and how to allocate resources between children at the end of the parents'' life. Optimal decision rules are those that maximize the number of grandchildren. Decisions are assumed to depend on the state of the parent, which is described at any time by two variables: number of living sons, and wealth. The dynamics of the model are based on a traditional African pastoralist system, but it is general enough to approximate to any means of subsistence where an increase in the amount of wealth owned increases the capacity for future production of resources. The model is used to show that, in the unpredictable environment of a traditional pastoralist society, high fertility and a biasing of wealth inheritance to a small number of children are frequently optimal. Most such societies are now undergoing a transition to lower fertility, known as the demographic transition. The effects on fertility and wealth inheritance strategies of reducing mortality risks, reducing the unpredictability of the environment and increasing the costs of raising children are explored. Reducing mortality has little effect on completed family sizes of living children or on the wealth they inherit. Increasing the costs of raising children decreases optimal fertility and increases the inheritance left to each child at each level of wealth, and has the potential to reduce fertility to very low levels. The results offer an explanation for why wealthy families are frequently also those with the smallest number of children in heterogeneous, post-transition societies.     

Do mothers-in-law matter? Family dynamics and fertility decision-making in urban squatter settlements of Karachi, Pakistan

The perspectives of mothers-in-law about intra-household decision-making, family size and family planning are investigated, and their views compared with those of their sons and daughters-in-law. Women (717 daughters-in-law), their husbands (717 sons) and their 522 mothers-in-law were interviewed in eight squatter settlements in Karachi, Pakistan. Decisions about the schooling and health care of children, and the purchase of jewellery, are perceived to lie within the nuclear family domain (i.e. husband and wife). There was a difference in mothers-in-law's, daughters-in-law's and sons' desire to have more children. Twenty-eight per cent of mothers-in-law versus 58%, of daughters-in-law did not want more grandsons/sons and 36%, of mothers-in-law versus 66% of daughters-in-law did not want more granddaughters/daughters. The difference was markedly greater among the mother-in-law/daughter-in-law pairs than in the mother/son pairs. Overall, the mother-in-law's role seems to be somewhat overshadowed by that of her son (family male member), except for limiting family size. It is suggested that mothers-in-law should be included in Information-Education-Communication (IEC) campaigns about family planning.     

Marital fertility in polygynous unions in Nigeria

The effect of polygyny on fertility, by age cohort, was examined in 4 regions of Nigeria through use of data from the 1981-82 Nigerian Fertility Survey. Simple tabulation of numbers of live births by maternal age and type of marriage union indicated that, with the exception of the 30-39-year age group, fertility in polygynous unions tends to be higher than that in monogamous marriages. Overall, such tabulations reveal an average of 3.90 births among polygynous women and 3.47 births among monogamous women. However, when age-specific fertility rates were compared, except for women under 20 and over 40 years of age, rates were higher in monogamous unions (7.286 overall) than for women in polygynous households (7.200 overall). Mean completed fertility, taking into account marriage duration as well, shows a tendency for women in polygynous unions to be more fertile (with the exception of women aged 25-44 years who had been married 10-19 years). The absolute difference in fertility between the 2 types of marital unions ranged from 0.32 children in the northwest to 0.64 in the southeast. With adjustment for independent variables such as education, the absolute mean differences were reduced, from between 0.28 children in the southeast to 0.42 in the northeast, but the direction of high fertility was still in favor of women in polygynous unions. But when the covariates (e.g., age at marriage) were taken into account as well as the independent variables, there was a dramatic reduction in the mean difference between the fertility of these 2 groups of women. These findings suggest that some changes in reproductive behavior are taking place in Nigeria that are restricting the fertility of women in polygynous unions. These changes are hypothesized to reflect the spread of formal education in Nigeria, with the expectation that women will contribute to the costs involved in educating their children.     

Harijans and Girijans of Andhra Pradesh: an application of analysis of variance in the study of fertility,mortality and family planning

Research on the Bagatha tribe and the Malas and Madigas in India has been done for economic and social planning purposes in regard to family planning. Bagatha are mostly agricultural people where the nuclear family is prevalent and polygamy is popular as well as cousin marriage. The Madigas and Males (Harijans) are lower caste with the 1st being leather workers and the latter being agricultural helpers. The data was collected by direct interview of 202 tribesmen and 202 caste households with women from 15-49 years of age. The data collected on fertility include live births, child survival rate, fetal wastage, husband and wives education, income, and occupations. On mortality, the number of deaths, age at marriage, number of and intervals of pregnancies. As expected, educated and employed families show healthier and higher levels of fertility especially if the wife is educated. The wife shows more of the responsibility for family planning. The age at marriage and the number of pregnancies appears to have little effect on mortality. In the caste group the education level of the husband has little effect on fertility and again the wife has the primary responsibility in using family planning techniques.     

Fertility and family planning in Papua New Guinea

This paper examines some of the data on fertility, family size and family planning from a survey conducted between November 1979 and March 1980 in 8 provinces both in rural and urban areas of Papua New Guinea (PNG). The sample consisted of 6283 male and female respondents; a total of 3986 females in the age group 15-49 and 2297 males between the ages of 20 and 54 were interviewed. About 9% of the rural and 5.4% of the urban female respondents were pregnant at the time of the interview. The higher number of pregnancies recorded for the rural population, compared to the urban, is due to longer duration of marriage and higher mean age. Both rural and urban respondents have similar attitudes to the ideal number of children. 4 and 6 children were indicated as an ideal number for the urban and rural population, respectively. The results indicate that economic pressures are being felt within the family in both urban and rural areas, and that the costs of raising children are clearly perceived, at least among the educated. Nonetheless, the majority of the population desires large numbers of children, the main reason being economic security in old age. It is also evident that the people have a negative attitude to modern methods of contraception because they are not well informed about them. The most frequently stated reason, the harmful effects on the health of the mother and future offspring, is probably one of the obstacles to their more widespread use. Though there is physical accessibility to family planning services for most urban and about 1/2 of the rural dwellers, the problems of non-use are mainly of a sociological and psychological nature. The problems include the attitude of husbands to their wives' use of contraceptives, reinforcement of culturally acceptable behavior by the extended family and community members, and the desire for more children. Although the levels of contraceptive awareness are relatively high, the overall impression is that the practice of modern contraception in both the rural and urban areas is low. Despite the rural-urban differences in educational and income levels, living conditions, and the availability of family planning services, awareness and current use are only slightly higher among the urban respondents. For family planning programs to have more impact in reducing the high fertility levels, a much more intensive program of activites is needed for the country at large.     

Correlations in fertility across generations: can low fertility persist?

Correlations in family size across generations could have a major influence on human population size in the future. Empirical studies have shown that the associations between the fertility of parents and the fertility of children are substantial and growing over time. Despite their potential long-term consequences, intergenerational fertility correlations have largely been ignored by researchers. We present a model of the fertility transition as a cultural process acting on new lifestyles associated with fertility. Differences in parental and social influences on the acquisition of these lifestyles result in intergenerational correlations in fertility. We show different scenarios for future population size based on models that disregard intergenerational correlations in fertility, models with fertility correlations and a single lifestyle, and models with fertility correlations and multiple lifestyles. We show that intergenerational fertility correlations will result in an increase in fertility over time. However, present low-fertility levels may persist if the rapid introduction of new cultural lifestyles continues into the future.     

Heritability of fertility in human populations and the structure of Crow's index

Heritability of fertility was determined in populations with natural character of reproduction (Middle Asia Republics) and in populations with family planning (Middle Russia). The material was collected by interviewing the married women of postreproductive age. The heritability of fertility was estimated as a doubled coefficient of correlations between sisters for effective fertility. In populations with natural character of reproduction the heritability was about 50% and it did not differ from O in the populations with family planning. The values of heritability were used in the components of the Crow index analysis. The main contribution into broad-sense heritability of fertility comes from additive component, as shown in an Asia population (Turkmen). The values of heritability of fecundability (86%) and of postpartum sterility (66%) have been calculated for the same population.     

Desired family size and sex of children in Nigeria

During 1981, sex ratio data and preferences for family size and for combinations and permutations of children were provided by 333 Nigerian students at the University of Ilorin, Ilorin, Nigeria. For the present and parental generations combined, the secondary sex ratio was estimated to be 95.8 males:100 females. In the projected families, preferences for family sizes resulted in an average of 4.88 children per family. The most preferred family consisted of four children--a 2m2f combination in a mfmf order, whereas the second most preferred family consisted of five children--3m2f combination in a mfmfm order. Also expressed was a strong preference for permutations of sexes, resulting in a male child as first-born followed by an alternation of sexes. A greater preference for male children was indicated by the combined sex ratio of 167 males:100 females for the preferred families.     

Ethnicity and fertility in Nigeria

Using a sample of Hausa-Fulani, Yoruba, Ibo, and all other women from the 1990 Nigerian Demographic and Health Survey, this study examines ethnic fertility differentials in Nigeria within the context of the social characteristics and cultural hypotheses. Among all women, we find the net fertility of Hausa-Fulani women to be lower than that of Other women; with no statistically significant difference in the net fertility of Ibo, Yourba, and Other women. But, among currently married women, we find the net fertility of Hausa-Fulani and Yoruba women to be lower than that of Other women, while the net fertility of Ibo women is higher than that of Other women. Overall, the findings of this study are more consistent with the cultural hypothesis, because statistically significant fertility differentials by ethnicity remain, even after controlling for selected socioeconomic and demographic variables.     

Spouses' socioeconomic characteristics and fertility differences in sub-Saharan Africa: does spouse's education matter?

Although the general objective of this study is to examine the extent to which spouses' socioeconomic characteristics determine whether modern contraception is used and whether family limitation (the demand for no more children) is desired, its central goal is to evaluate the degree to which the net effect of a woman's education on those fertility decisions is altered once a control is made for the level of schooling of the husband. Individual characteristics of spouses included as controls in this analysis are on the one hand women's attributes relating to employment, age, parity, ethnic identity, and urban residence and, on the other hand, the occupation of the husband. Data used in this research are provided by DHS surveys conducted in fourteen sub-Saharan countries: Mali. Burkina Faso, Niger, Nigeria, Cameroon, Benin, Senegal. Ghana, Central African Republic, Kenya, Zambia, Zimbabwe, Namibia and Rwanda. With two dichotomous outcome variables, logistic regression was used to estimate two nested models for each dependent variable and for each country covered by the study. DHS respondents used as units of analysis in this study are women who were married (any kind of union) and non-pregnant at the time when each national survey was conducted. The findings suggest that, while an educated wife needs the support of an educated husband to state a preference for family limitation in contemporary sub-Saharan Africa, controlling for husband's education and other relevant covariates does little to undermine the evidence that woman's advanced education and the adoption of modern family planning are positively related in the developing world.     

Fitness and fertility among Kalahari !Kung

In this paper we develop a model that examines fertility and childhood mortality patterns and their relationship to environmental variables. Interactions among environmental variables can account for different fertility patterns and different mixes of these variables can produce similar patterns of fertility. Our model attempts to quantify the idea that there is a trade-off between producing a few children likely to survive to reproductive age and producing a greater number of children with lower chances for survival. The optimum mix of these strategies depends on environmental characteristics. We use the model to make predictions about fertility and mortality patterns among two Bushmen populations of southern Africa--the Ghanzi and Ngamiland !Kung--using data collected by Harpending in 1967-1968. The results do not support explanations of the low fertilities observed among !Kung Bushmen women, in whom it is thought that fitness is maximized by limiting fertility, and show no relationship between mortality and family size in either !Kung population. Instead, the number of offspring reaching reproductive age in both populations increases as their completed family size increases. We examine the effects of sex, birth order, and paternal investment on mortality. No sex ratio differences and no differences in mortality by sex or birth order are present. Infant mortality among women who married more than once is significantly higher than among women who married once, suggesting that paternal care has a significant effect.     

Human fertility and fitness optimization

Census and other survey data from across the world reveal major differences in fertility rates between the more economically developed and the less economically developed societies. The former are significantly more likely than the latter to feature families of two children or fewer. Multiple regression analysis shows that, among various indicators of “modernization,” three (female level of education, female gainful employment, and proportion of physicians in the population) account for 71% of the variation in family size; all three variables have strongly significant, direct, and negative effects on fertility. The paper hypothesizes about the possible evolution of a reproductive psychology toward the two-child family and seeks to explain highly depressed rates of reproduction by reference to both ultimate and proximate factors. In some highly developed countries, zero-child and one-child rates of fertility represent together up to 40% of all ever-married women. The findings stress the importance of systematic research toward establishing the proximate factors that are most likely to facilitate or impede fitness optimization—the importance, that is, of surrounding the optimization principle with the logic and ancillary propositions that will give it a greater and more directive reach.     

Contraceptive knowledge and attitudes in urban Ilorin, Nigeria

In Nigeria as in other African countries, population growth negatively affects economic development, and high parity affects maternal health. Breastfeeding, a common practice traditionally, is declining in some situations. This study was carried out in Ilorin, Nigeria. A sample population of 932 households stratified to represent different socioeconomic groups was used. 913 currently married women aged 15-35, who were in their prime childbearing ages, were interviewed on their contraceptive knowledge and on their attitudes towards modern contraception. In a bivariate statistical analysis, of 8 variables examined (i.e. ownership of a television, radio, religion, and other) only the woman's education, age, and area of residence within the city have significant independent effects on contraceptive knowledge. A linear logistic regression technic was also applied. 90% of the women interviewed thought that women should be free to practise family planning. Also, 95% of all the women believed that too frequent births could endanger the health of the mother and her children. Only the women with previous contraceptive knowledge overwhelmingly (80%) thought that the best way to prevent too frequent births is by family planning. 66.5% of those without previous contraceptive knowledge before this study suggested that traditional abstinence should be used and only 28.9% suggested family planning. Adequate awareness of the availability and usefulness of family planning methods can influence attitudes of women towards contraception and may also enhance contraceptive use. Better use can be made of broadcasting media, and efforts should be made to target younger, more fecund women, since there was evidence that more knowledge of family planning existed among women 30+ years old.     

Ideal versus actual: the contradiction in number of children born to Nigerian women

Although desired family size is often different from actual family size, the dynamics of this difference are not well understood. This paper examines the patterns and determinants of the difference between desired and actual number of children (unmet fertility desires) among women aged 15-49 years using pooled data from the 1990, 1999 and 2003 Nigeria Demographic and Health Surveys (NDHSs). The results show that more than two-thirds of the sample have unmet fertility desires (18.1% have more while 52.4% have fewer than desired). It was found that early and late childbearing increased the odds of unmet fertility desires. Also, women with low levels of education, from poor households, rural residents as well as those who had experienced child death were at a higher risk of unmet fertility desires in the multivariate context. The study highlights the policy and programme implications of the findings.     

Empowerment in family planning as viewed by Iranian women: a qualitative study

Women carry the primary responsibility for family planning in most parts of the world, and should be afforded the power of decision-making and control over their fertility. This study seeks to gain insight into Iranian women's perception of the meaning of empowerment in family planning. Using a qualitative study, seven focus group discussions and five individual interviews were conducted with 35 married Iranian women of reproductive age. The data were analysed using a conventional content analysis approach, in which themes and categories were explored to reveal women's experiences of empowerment in family planning. The results demonstrated four main categories: control over fertility plan, participative family planning, maintaining health and access to optimal family planning services. They viewed knowledge of family planning and autonomy of decision-making in fertility issues as essential elements for control of their fertility plan. Participants felt more empowered when joint family planning decisions were made with their partners in an atmosphere of agreement. Therefore, family planning policymakers should plan services with new approaches that focus on women's health and empowerment.     

Wealth,fertility and adaptive behaviour in industrial populations

The lack of association between wealth and fertility in contemporary industrialized populations has often been used to question the value of an evolutionary perspective on human behaviour. Here, we first present the history of this debate, and the evolutionary explanations for why wealth and fertility (the number of children) are decoupled in modern industrial settings. We suggest that the nature of the relationship between wealth and fertility remains an open question because of the multi-faceted nature of wealth, and because existing cross-sectional studies are ambiguous with respect to how material wealth and fertility are linked. A literature review of longitudinal studies on wealth and fertility shows that the majority of these report positive effects of wealth, although levels of fertility seem to fall below those that would maximize fitness. We emphasize that reproductive decision-making reflects a complex interplay between individual and societal factors that resists simple evolutionary interpretation, and highlight the role of economic insecurity in fertility decisions. We conclude by discussing whether the wealth–fertility relationship can inform us about the adaptiveness of modern fertility behaviour, and argue against simplistic claims regarding maladaptive behaviour in humans.