Polygyny, reproductive success and child health in rural Ethiopia: why marry a married man?

Socio-demographic determinants of intimate partner violence in Angola: a cross-sectional study of nationally representative survey data

Intimate Partner Violence (IPV) is a global problem of public health importance, which can be found across all social layers and cultural backgrounds worldwide. Angola is still an under-explored country in the context of domestic violence and was therefore chosen as our focus of interest. Our study's goal was to identify the socio-demographic determinants of IPV in Angola. We used nationally representative data from female respondents of the 2015 Angolan Demographic and Health Surveys (DHS). Simple bivariate and multiple logistic regression analyses were used to assess the relationship between the experience of IPV and the women's' individual and contextual characteristics. Out of the 7,699 respondents, 3,070 (41.1%) reported having experienced at least one form of violence by their partners, with physical violence being more prevalent (32.5%) than emotional (27.7%) and sexual violence (7.2%). The partner's use of alcohol, the respondent's tendency to hurt her partner, her having witnessed her father beating her mother and being the first wife showed significantly higher odds of experiencing one or more types of IPV, whereas being older than the partner appears to have protective effects. Our findings reflect the widespread prevalence rates of violence against women in African countries. Future intervention programs should focus on women with risky background characteristics to help decrease domestic abuse in Angola. Our results indicate to focus on young women who have witnessed domestic violence in childhood, those whose partners use alcohol and those who tend to physically hurt their partners themselves. It is also recommended to intensify future research on the effects of co-wives on a relationship since first wives were found to have a higher risk of being physically abused by their partners.

Genetic variants underlying human bisexual behavior are reproductively advantageous

Because human same-sex sexual behavior (SSB) is heritable and leads to fewer offspring, how SSB-associated alleles have persisted and whether they will remain in human populations are of interest. Using the UK Biobank, we address these questions separately for bisexual behavior (BSB) and exclusive SSB (eSSB) after confirming their genetic distinction. We discover that male BSB is genetically positively correlated with the number of offspring. This unexpected phenomenon is attributable to the horizontal pleiotropy of male risk-taking behavior-associated alleles because male risk-taking behavior is genetically positively correlated with both BSB and the number of offspring and because genetically controlling male risk-taking behavior abolishes the genetic correlation between male BSB and the number of offspring. By contrast, eSSB is genetically negatively correlated with the number of offspring. Our results suggest that male BSB-associated alleles are likely reproductively advantageous, which may explain their past persistence and predict their future maintenance, and that eSSB-associated alleles are likely being selected against at present.

Abandoning female genital mutilation/cutting (FGMC) is an emerging but costly parental investment strategy in rural Ethiopia

Female genital mutilation or cutting (FGMC) has profound consequences for an estimated 200 million women world-wide, yet affected communities often resist efforts to end the practice. Marriage market dynamics have been proposed as key to this resistance, because where FGMC is normative, parents are motivated to cut their daughters to improve their marriage prospects. Some economists have also argued that financial gain, through bride wealth payments, incentivises parents to cut daughter's at time of marriage. Bride wealth, however, does not necessarily equal net economic return, confounding efforts to test this assumption. Here we use detailed data on the financial value of all exchanges at marriage from Ethiopian Arsi Oromo agropastoralists to assess their association with FGMC. We also explore the idea that parents must replace FGMC with other forms of investment (e.g., education) when cutting practices are rejected. Multivariate multilevel Bayesian models were run using data from the first marriages of 358 women to assess the association between FGMC status and education and marriage-related outcomes: bride wealth payments, dowry costs, and age at marriage. Being cut is associated with lower dowry costs and earlier age at marriage but does not predict bride wealth paid by the groom's family. School attendance is associated with higher bride wealth, particularly for women with four or more years of education, and with later age at marriage. These findings indicate that bride wealth payments do not maintain FGMC among the Arsi Oromo. While we find a relative economic loss for parents from FGMC abandonment through higher value dowry gifts, this may be traded-off against the health benefits to uncut daughters. These findings point to the emergence of new norms, whereby Arsi Oromo parents reject cutting for their daughters and prefer their daughters-in-law to be educated.

Contraception ends the genetic maintenance of human same-sex sexual behavior

Because human same-sex sexual behavior (SSB) is heritable and leads to fewer offspring, it is puzzling why SSB-associated alleles have not been selectively purged. Current evidence supports the antagonistic pleiotropy hypothesis that SSB-associated alleles benefit individuals exclusively performing opposite-sex sexual behavior by increasing their number of sexual partners and consequently their number of offspring. However, by analyzing the UK Biobank, here, we show that having more sexual partners no longer predicts more offspring since the availability of oral contraceptives in the 1960s and that SSB is now genetically negatively correlated with the number of offspring, suggesting a loss of SSB's genetic maintenance in modern societies.

Contraception ends the genetic maintenance of human same-sex sexual behavior

Because human same-sex sexual behavior (SSB) is heritable and leads to fewer offspring, it is puzzling why SSB-associated alleles have not been selectively purged. Current evidence supports the antagonistic pleiotropy hypothesis that SSB-associated alleles benefit individuals exclusively performing opposite-sex sexual behavior by increasing their number of sexual partners and consequently their number of offspring. However, here we show that having more sexual partners no longer predicts more offspring since the availability of oral contraceptives in the 1960s and that SSB is now negatively genetically correlated with the number of offspring, indicating a loss of SSB’s genetic maintenance in modern societies.

Contraceptive utilization and associated factors among polygamous and monogamous women in Worebabo Woreda, South Wollo Zone, Ethiopia: a comparative cross sectional study

BACKGROUND

In Ethiopia high population growth and unintended pregnancies are posing pressures where the economy is incapable of holding overpopulation. Despite this problem, utilization of modern contraception is low in rural areas of the country, especially in the areas where polygamy is common. Therefore, this study was conducted to assess contraceptive utilization and associated factors among polygamous and monogamous women in, Ethiopia.

METHOD

A community-based comparative cross-sectional and phenomenological study design was employed from July 1 to September 30, 2021, on the total sample size of 774 selected married women of the reproductive age group by using a multistage sampling method and a purposive sampling method were used for the qualitative part of the study. A pre-tested interview with a structured questionnaire was used to collect data and key informants were interviewed using semi-structured questionnaire. Associated factors were analyzed by using bivariable and multivariable binary logistic regression models. The odds ratio, with a 95% confidence level, was used to declare a statistically significant association.

RESULT

A total of 703 married women of the reproductive age groups were interviewed, yielding a 90.89% response rate; among these married women, 352 and 351 were in monogamous and polygamous relationships. The proportion of women who use modern contraceptives was 161 (45.7%) in monogamous relationship, and 151 (43.0%) in polygamous relationships. Overall, utilization of modern contraceptives was significantly associated with educational status (AOR = 2.143, CI:1.428-3.216), religion (AOR = 1.704, CI: 1.144-2.539), undesired fertility (AOR = 3.17,CI:1.939-5.183), who decides on the number of children (AOR = 3.054, CI:1.93-4.832), getting clear information by Health care provider (AOR = 4.624, CI:3.132-6.828), family pressure (AOR = 1.855, CI:1.351-2.75), fear of social stigma (AOR = 2.482, CI:1.666-3.699), and accepts myths about contraceptives (AOR = 1.878, CI:1.278-2.761).

CONCLUSION

This study identified that utilization of modern contraception was low in the study area. The district health office and concerned stakeholders should implement interventions that scale up contraceptive use, need family involvement in decision making, addressing myths around contraceptives, helping women to get education, and training of health care providers.

Integrating economic and evolutionary approaches to polygynous marriage

We outline the potential for integrating economic and evolutionary approaches to marriage and the family. Our broad argument is that the approaches share a concern for competition. Evolutionary scholars are concerned with the fitness consequences of competition and economists are centrally concerned with the nature of competition: how the allocation of scarce resources is mediated by potentially complex forms of social interaction and conflicts of interest. We illustrate our argument by focusing on conceptual and empirical approaches to a topic of interest to economists and evolutionary scholars: polygynous marriage. In comparing conceptual approaches, we distinguish between those that emphasise the physical environment and those that emphasise the social environment. We discuss some advantages of analysing marriage through the lens of competitive markets, and outline some of the ways that economists analyse the emergence of rules governing the family. In discussing empirical approaches to polygynous marriage, we describe how a concern for informing contemporary policy leads economists to focus on the consequences of polygyny, and in particular we describe some of the ways in which economists attempt to distinguish causal effects from selection effects.

Revisiting the polygyny and intimate partner violence connection: The role of religion and wife's rank in Nigeria

Objective

The study examines the association between polygyny and intimate partner violence (IPV) by focusing on the Muslim-vs.-Christian context of polygyny and on co-wives' rank.

Background

Although prior research points to a higher incidence of IPV in polygynous unions, the association between polygyny and IPV are not well understood. In particular, the role of broader cultural and religious context of marriage and its connection with intra-marital dynamics have not been examined.

Method

The study uses pooled data on over 42,000 women from the 2008, 2013 and 2018 rounds of the Nigeria Demographic and Health Survey to examine the association of polygynous versus monogamous status of marriage, of Muslim versus Christian religious affiliation, and of co-wife rank within polygynous unions in both religions with women's reported experience of physical, emotional, and sexual IPV. Multivariate logit and propensity score models (PSM) are fitted, and the Rosenbaum bounds test is used to gauge the robustness of PSM results.

Results

Results show a clear disadvantage of polygynously married women, compared to monogamously married ones; IPV experience is more common among Christians than Muslims. Among women in polygynous marriages, senior wives are more likely to experience IPV than junior wives, but this difference is more pronounced among Christians. Results of a Rosenbaum bounds analysis indicate that unobserved selectivity does not present a challenge to causality between polygyny/wife rank and IPV, particularly when analyses are disaggregated by religion.

Conclusion

Findings reflect multi-dimensional gender inequalities embedded in the institution of polygynous marriage and their harmful consequences for women's health and well-being.

Multilevel analysis of determinants of polygyny among married men in Ethiopia

BACKGROUND

Polygyny occurs when a man has more than one wife at the same time. It often contributes to poor health among family members, particularly young children. It encourages the spread of sexually transmitted infections (STIs) including HIV/AIDS. The determinants of polygyny have not yet been adequately explored in Ethiopia. This study adds to the body of knowledge concerning the prevalence and distribution of polygyny in the country.

METHODS

This study is a secondary analysis of the 2016 Ethiopian Demographic and Health Survey (EDHS) data. Using a two-stage stratified cluster sampling, 7470 married men were selected. After verifying the assumptions of multilevel logistic regression analysis, Stata version 14.0 was used to analyse the data. A multilevel mixed-effects logistic regression model was used to identify predictors of polygyny. An adjusted odds ratio with a 95% confidence interval was used to measure the association. A p-value of < 0.05 was considered to indicate statistical significance.

RESULTS

Age from 30 to 44 years [AOR = 5.78, 95% CI = (3.13, 10.7)], age from 45 to 59 years [AOR = 16.5, 95% CI = (8.59, 31.8)], men with primary education or no formal education [AOR = 3.40, 95% CI = (1.50, 7.69)], being Muslim [AOR = 2.47, 95% CI = (1.28, 4.77)], sexual initiation at or above the age of 18 years [AOR = 0.46, 95% CI = (0.30, 0.68)] and being from a less developed region of Ethiopia [AOR = 3.67, 95% CI = (2.30, 5.83)] were factors associated with polygyny.

CONCLUSION

Both individual and community level factors were identified as predictors of polygyny. Improving educational attainment and delaying men's sexual debut could encourage the reduction of polygyny in Ethiopia.

Intimate partner violence, contextual factors and under-5 mortality: a multilevel analysis of cross-sectional surveys from 20 Sub-Saharan African countries

BACKGROUND

Under-5 mortality remains a public health concern in low-income and middle-income countries. Africa contributes about one-fifth of the burden of global under-5 mortality; intimate partner violence (IPV) and polygyny, which are highly prevalent on the continent, have been linked to under-5 mortality at the individual level. This study examined the relationship between IPV and polygyny as contextual factors and the experience of under-5 mortality among women in Sub-Saharan Africa (SSA).

METHODS

We used data from the Demographic and Health Surveys (DHS) of 20 African countries with available data between 2010 and 2018 as of April 2020. We defined the experience of under-5 mortality as a woman's loss of at least one child before their fifth birthday. The DHS primary sampling unit was used to define contextual factors. The study involved a multilevel logistic regression analysis of 227 121 women of childbearing age (15-49).

RESULTS

A quarter (24.5%) of women have lost at least one child under 5 years old, more than two-thirds (40.1%) have experienced at least one form of IPV, and about two-thirds of women were in polygynous union. Our multilevel logistic regression showed that parity, polygynous union and experience of IPV were strongly associated with women's experience of under-5 mortality. The results showed that 39.9% and 19.2% of variances in odds of a woman losing a child before their fifth birthday are attributable to community-level and country-level factors, respectively. Contextual prevalence of IPV, polygynous union and gender equity attenuate the strength of associations observed at the individual level. The interaction between contextual prevalence of polygyny and IPV exacerbates the risk of under-5 mortality. Women in SSA countries with higher Human Development Index were less likely to experience under-5 mortality.

CONCLUSION

This study established that beyond individual-level effects, contextual prevalence of IPV and polygyny and their interactions shape women's experience of under-5 mortality in Africa. In designing policies and interventions to address under-5 mortality, contextual factors, especially those linked to culturally laden social norms and practices, must be considered to ensure effectiveness and sustainable impact.

Undernutrition, polygynous context and family structure: a multilevel analysis of cross-sectional surveys of 350 000 mother-child pairs from 32 countries

BACKGROUND

Contextual factors, especially where people live, has been linked to various health outcomes, therefore, there is an increasing focus on its implication for policies and implementation of health interventions. Polygyny is a widespread practice in sub-Saharan Africa that also reflects socioeconomic and sociocultural features. This study investigated the association between polygynous context and risk of undernutrition.

METHODS

Recent Demographic and Health Surveys involving 350 000 mother-child pairs from 32 sub-Saharan African countries conducted between 2010 and 2018 as of March 2020, were analysed using relevant descriptive and 3-level multilevel logistic regression modelling. Undernutrition among under-5 was defined as underweight, stunting and wasting using the WHO Multicentre Growth Reference Study. Odd Ratio (OR) at 95% credible interval was used to report the associations.

RESULTS

The prevalence of contextual polygyny varied widely across the 32 sub-Saharan African countries, the lowest (0%) found in one of the regions in South Africa and the highest (52%) in one of the regions in Uganda. Underweight, stunting and wasting were lowest in Uganda (3.5%, 9.3%-1.27%, respectively), stunting was highest in Mozambique (37.1%) while wasting was highest in Niger (7.7%). Furthermore, the results showed that the contextual prevalence of polygynous practice exacerbates the risk of underweight (1.003 (0.997-1.008)) and wasting (1.014 (1.007-1.021)) among under-5 children, even when gender inequality and sociodemographic indicators were adjusted for. Polygyny was negatively associated with stunting though not significant; multiple births had the strongest and positive association with the risk of undernutrition among under-5 children in sub-Saharan Africa.

CONCLUSIONS

This study further corroborates the strong influence of contextual factors on health outcomes-which is undernutrition in this study. In addition to specific interventions aimed at reducing the prevalence of undernutrition, broader strategies that will address contextual issues are required.

The Effects of Marital Status, Fertility, and Bereavement on Adult Mortality in Polygamous and Monogamous Households: Evidence From the Utah Population Database

Although the associations among marital status, fertility, bereavement, and adult mortality have been widely studied, much less is known about these associations in polygamous households, which remain prevalent across much of the world. We use data from the Utah Population Database on 110,890 women and 106,979 men born up to 1900, with mortality follow-up into the twentieth century. We examine how the number of wife deaths affects male mortality in polygamous marriages, how sister wife deaths affect female mortality in polygamous marriages relative to the death of a husband, and how marriage order affects the mortality of women in polygamous marriages. We also examine how the number of children ever born and child deaths affect the mortality of men and women as well as variation across monogamous and polygamous unions. Our analyses of women show that the death of a husband and the death of a sister wife have similar effects on mortality. Marriage order does not play a role in the mortality of women in polygamous marriages. For men, the death of one wife in a polygamous marriage increases mortality to a lesser extent than it does for men in monogamous marriages. For polygamous men, losing additional wives has a dose-response effect. Both child deaths and lower fertility are associated with higher mortality. We consistently find that the presence of other kin in the household—whether a second wife, a sister wife, or children—mitigates the negative effects of bereavement.

Inequality in the household and rural-urban migration in Ethiopian farmers

Parental investment theory predicts that biases in investment favour migration by driving some of the sibling group to disperse for resources. Here we test hypotheses arising from this theory to explain patterns of rural-urban migration in south-central Ethiopia considering familial and individual strategies. We focus on the migration of low-skilled men, predicting two scenarios based on a low level of resource availability. Firstly, last-born sons will be more likely to migrate in order to offset their intra-household disadvantage when resources are limited (sibling competition). Alternatively, in households facing livelihood insecurity, older sons will migrate in order to free resources for their younger dependant brothers (reflecting sibling cooperation). Demographic, economic and relational data were collected from 217 families of male migrants, including information for 830 male adults. We performed multivariate analyses, including Bayesian generalised linear models and mixed models, to analyse quantitative data with a focus on household and individual likelihood of out-migration. Consistent with the predictions from parental investment theory, migration is dependent on intra-household resource allocation. Depending on the stage of the family cycle and livelihood context, families and individuals present different strategies: labour migration may result from sibling competition or from cooperation for resource enhancement.

Condemned and Condoned: Polygynous Marriage in Christian Africa

OBJECTIVE

This study contributes to a better understanding of the role of Christianity in the persistence of polygyny in sub-Saharan Africa.

BACKGROUND

Marital systems and practices are closely connected to religious norms, but these connections are often complex and contradictory. Polygynous marriage remains widespread in sub-Saharan Africa, including its heavily Christianized parts, where public opposition to it should be strongest.

METHODS

The study analyzes a rich combination of quantitative and qualitative data from a predominantly Christian district in Mozambique. The data include a household-based survey, a census of the district's religious congregations, and focus group discussions and individual interviews with leaders and rank-and-file members of various churches.

RESULTS

The multivariate statistical tests point to instructive denominational differences in the prevalence and acceptance of polygyny, with the starkest contrast being between two types of African Initiated Churches - one that is more lenient on pre-Christian practices and the other that is vehemently opposed to them. These tests also show a contrast between church leaders and rank-and-file members, the latter being generally more accepting of polygyny, and illustrate variations in acceptability of polygyny across different church membership scenarios. The analysis of the qualitative data complements the statistical tests by highlighting ideological and social mechanisms through which polygynous marriage is both rejected and legitimized in Christian communities.

CONCLUSION

Both condemnation and toleration of polygyny by Christian churches reflect the complexities of the transformation of sub-Saharan marital systems and of the role that religion plays in that process.

Polygyny and Intimate Partner Violence in Mozambique

Polygyny has shown a positive association with intimate partner violence (IPV), yet the nature and mechanisms of this association are not well understood. This study uses data from rural Mozambique to distinguish women in polygynous unions by rank and co-residence. Findings show that senior wives report higher rates of violence than their junior-wife and monogamously married counterparts. At the same time, no difference is detected between junior wives and women in monogamous marriages. Additionally, the analysis finds that polygynously married women living away from their co-wives report higher rates of violence than both women co-residing with co-wives and women in monogamous unions, while the difference between the latter two categories is not statistically significant. However, the results also indicate that senior wives living away from their co-wives face particularly high risks of violence. These findings illustrate the social complexity of polygynous marriages and resulting differential vulnerabilities of women in them.

Evolutionary perspective on sex differences in the expression of neurological diseases

Sex-specific brain and cognitive deficits emerge with malnutrition, some infectious and neurodegenerative diseases, and often with prenatal or postnatal toxin exposure. These deficits are described in disparate literatures and are generally not linked to one another. Sexual selection may provide a unifying framework that integrates our understanding of these deficits and provides direction for future studies of sex-specific vulnerabilities. Sexually selected traits are those that have evolved to facilitate competition for reproductive resources or that influence mate choices, and are often larger and more complex than other traits. Critically, malnutrition, disease, chronic social stress, and exposure to man-made toxins compromise the development and expression of sexually selected traits more strongly than that of other traits. The fundamental mechanism underlying vulnerability might be the efficiency of mitochondrial energy capture and control of oxidative stress that in turn links these traits to current advances in neuroenergetics, stress endocrinology, and toxicology. The key idea is that the elaboration of these cognitive abilities, with more underlying gray matter or more extensive inter-modular white matter connections, makes them particularly sensitive to disruptions in mitochondrial functioning and oxidative stress. A framework of human sexually selected cognitive abilities and underlying brain systems is proposed and used to organize what is currently known about sex-specific vulnerabilities.

Indirect questioning method reveals hidden support for female genital cutting in South Central Ethiopia

Female genital cutting (FGC) has major implications for women’s physical, sexual and psychological health, and eliminating the practice is a key target for public health policy-makers. To date one of the main barriers to achieving this has been an inability to infer privately-held views on FGC within communities where it is prevalent. As a sensitive (and often illegal) topic, people are anticipated to hide their true support for the practice when questioned directly. Here we use an indirect questioning method (unmatched count technique) to identify hidden support for FGC in a rural South Central Ethiopian community where the practice is common, but thought to be in decline. Employing a socio-demographic household survey of 1620 Arsi Oromo adults, which incorporated both direct and indirect direct response (unmatched count) techniques we compare directly-stated versus privately-held views in support of FGC, and individual variation in responses by age, gender and education and target female (daughters versus daughters-in-law). Both genders express low support for FGC when questioned directly, while indirect methods reveal substantially higher acceptance (of cutting both daughters and daughters-in-law). Educated adults (those who have attended school) are privately more supportive of the practice than they are prepared to admit openly to an interviewer, indicating that education may heighten secrecy rather than decrease support for FGC. Older individuals hold the strongest views in favour of FGC (particularly educated older males), but they are also more inclined to conceal their support for FGC when questioned directly. As these elders represent the most influential members of society, their hidden support for FGC may constitute a pivotal barrier to eliminating the practice in this community. Our results demonstrate the great potential for indirect questioning methods to advance knowledge and inform policy on culturally-sensitive topics like FGC; providing more reliable data and improving understanding of the “true” drivers of FGC.

Assessment of Contraceptive Use by Marriage Type Among Sexually Active Men in Nigeria

Marital status, from the perspective of men (and especially sexually active men), as a potential factor that influences contraceptive use for the purposes of fertility control, has received little consideration in the scientific literature. This study thus assesses contraceptive use among sexually active men occupying different marital statuses. The study employed the 2013 Nigeria Demographic and Health Survey dataset. Using a total sample of 11,476 weighted sexually active men, the study revealed that 30% of the sampled population were currently using contraceptives, with condom as the dominant method (65.9%). The unadjusted odds of contraceptive use was significantly higher (9.4; confidence interval [8.1, 10.9]) among single men than married. Other factors include wealth, educational attainment, ethnicity, region, religion, and age. The study concludes that there are significant differences in contraceptive use between the single and married men and, therefore, recommends that policy and programs be put in place to promote consistent use of contraceptives among married men in Nigeria.

Fertility and Life Satisfaction in Rural Ethiopia

Despite recent strong interest in the link between fertility and subjective well-being, the focus has centered on developed countries. For poorer countries, in contrast, the relationship remains rather elusive. Using a well-established panel survey—the Ethiopian Rural Household Survey (ERHS)—we investigate the empirical relationship between fertility and life satisfaction in rural Ethiopia, the largest landlocked country in Africa. Consistent with the fertility theories for developing countries and with the sociodemographic characteristics of rural Ethiopia, we hypothesize that this relationship varies by gender and across life stages, being more positive for men and for parents in old age. Indeed, our results suggest that older men benefit the most in terms of life satisfaction from having a large number of children, while the recent birth of a child is detrimental for the subjective well-being of women at reproductive ages. We address endogeneity issues by using lagged life satisfaction in ordinary least squares regressions, through fixed-effects estimation and the use of instrumental variables.

Women's narratives of living in polygamous marriages: Rural Malawian experience distilled and preserved in poetic constructions

Polygamy in sub-Saharan Africa has been linked to poverty, infant mortality, and HIV; however, it is unknown how interpersonal dynamics within polygamous households may influence population health outcomes. Findings from this postcolonial feminist study derive from interview data in a larger mixed-methods study in rural Malawi. We used thematic narrative analysis to probe 25 women's stories and applied an arts-based research technique, poetic construction, to present the results. Participants' evocative expressions, distilled and preserved in poetic form, illustrate themes of perseverance, grief, agency, and reflection. We discuss how gender relations, childrearing, tradition, economics, and health intersect in polygamous households.

MARRIAGE GAP IN CHRISTIANS AND MUSLIMS

For modern Western societies with a regime of monogamy, it has recently been demonstrated that the socioeconomic status of men is positively associated with being or having been married. This study aims to compare marriage patterns (if a person has been married at least once) for cultures with a tradition of monogamy and polygyny. As no worldwide data on polygyny exist, religion was used as a proxy for monogamy (Christians) vs polygyny (Muslims). The analyses were based on 2000-2011 census data from 39 countries worldwide for 52,339,594 men and women, controlling for sex, sex ratio, age, education, migration within the last 5 years and employment. Overall, a higher proportion of Muslims were married compared with Christians, but the difference in the fraction of married men compared with married women at a certain age (the 'marriage gap') was much more pronounced in Muslims than in Christians, i.e. compared with Christians, a substantially higher proportion of Muslim women than men were married up to the age of approximately 31 years. As expected for a tradition of polygyny, the results indicate that the socioeconomic threshold for entering marriage is higher for Muslim than Christian men, and Muslim women in particular face a negative effect of socioeconomic status on the probability of ever being married. The large 'marriage gap' at a certain age in Muslim societies leads to high numbers of married women and unmarried young men, and may put such polygenic societies under pressure.

Productivity, Rank, and Returns in Polygamy

This study sheds light on the development of family structures in a polygamous context with a particular emphasis on wife order, and offers an explanation for the association between outcomes of children and the status of their mothers among wives based on observable maternal characteristics. In a simple framework, I propose that selection into rank among wives with respect to female productivity takes place: highly productive women are more strongly demanded in the marriage market than less productive women, giving them a higher chance of becoming first wives. Furthermore, productivity is positively associated with a wife's bargained share of family income to be spent on consumption and investment for herself and her offspring because of greater contributions to family income and larger outside options. The findings are empirically supported by a positive relationship between indicators of female productivity and women's levels of seniority among wives, and by a concise replication of existing evidence relating wife order to children's educational outcomes in household survey data from rural Ethiopia.

No evidence that polygynous marriage is a harmful cultural practice in northern Tanzania

Polygyny is cross-culturally common and a topic of considerable academic and policy interest, often deemed a harmful cultural practice serving the interests of men contrary to those of women and children. Supporting this view, large-scale studies of national African demographic surveys consistently demonstrate that poor child health outcomes are concentrated in polygynous households. Negative population-level associations between polygyny and well-being have also been reported, consistent with the hypothesis that modern transitions to socially imposed monogamy are driven by cultural group selection. We challenge the consensus view that polygyny is harmful, drawing on multilevel data from 56 ethnically diverse Tanzanian villages. We first demonstrate the vulnerability of aggregated data to confounding between ecological and individual determinants of health; while across villages polygyny is associated with poor child health and low food security, such relationships are absent or reversed within villages, particularly when children and fathers are coresident. We then provide data indicating that the costs of sharing a husband are offset by greater wealth (land and livestock) of polygynous households. These results are consistent with models of polygyny based on female choice. Finally, we show that village-level negative associations between polygyny prevalence, food security, and child health are fully accounted for by underlying differences in ecological vulnerability (rainfall) and socioeconomic marginalization (access to education). We highlight the need for improved, culturally sensitive measurement tools and appropriate scales of analysis in studies of polygyny and other purportedly harmful practices and discuss the relevance of our results to theoretical accounts of marriage and contemporary population policy.

Does Investment in the Sexes Differ When Fathers Are Absent? : Sex-biased Infant Survival and Child Growth in Rural Ethiopia

This study examines child survival and growth in a patrilineal Ethiopian community as a function of father absence and sex. In line with evolutionary predictions for sex-biased parental investment, the absence of a father and associated constraints on household resources is more detrimental for sons' than daughters' survival in infancy. Father absence doubles a son's risk of dying in infancy but has a positive influence on the well-being of female members of the household, improving daughter survival, growth, and maternal nutritional status. Lack of paternal investment may be compensated for by other matrilateral kin through increased reciprocity between mother, daughter, and sister.

Perceptions of polygyny: the effects of offspring and other kin on co-wife satisfaction

The costs and benefits of polygyny have been widely debated and vary according to local sociopolitical context, the level of female autonomy, and economic considerations such as the mode of production. This study aims to understand perceptions of polygyny as a function of household demography, particularly the number of female kin present in the household who can provide labor that is largely substitutable to that of a co-wife. The presence of these helpers is proposed to shift the cost-benefit structure of polygyny, in which having more female kin available is associated with a more negative view of the practice. Interview and census data from 106 Himba women, who are traditional, seminomadic pastoralists, were used to test this prediction. Among married women who reside patrilocally, the presence of more elder daughters was associated with a more negative view of polygyny. Among unmarried women, who reside in their natal homes, it is the total number of adult female kin that predicts perception of polygyny. In addition, unmarried women are significantly more likely to report fights over resources as a source of co-wife conflicts when they have more dependent children, but no such association was found among married women.

Polygynous contexts, family structure, and infant mortality in sub-saharan Africa

Contextual characteristics influence infant mortality above and beyond family-level factors. The widespread practice of polygyny is one feature of many sub-Saharan African contexts that may be relevant to understanding patterns of infant mortality. Building on evidence that the prevalence of polygyny reflects broader economic, social, and cultural features and that it has implications for how families engage in the practice, we investigate whether and how the prevalence of polygyny (1) spills over to elevate infant mortality for all families, and (2) conditions the survival disadvantage for children living in polygynous families (i.e., compared with monogamous families). We use data from Demographic and Health Surveys to estimate multilevel hazard models that identify associations between infant mortality and region-level prevalence of polygyny for 236,336 children in 260 subnational regions across 29 sub-Saharan African countries. We find little evidence that the prevalence of polygyny influences mortality for infants in nonpolygynous households net of region-level socioeconomic factors and gender inequality. However, the prevalence of polygyny significantly amplifies the survival disadvantage for infants in polygynous families. Our findings demonstrate that considering the broader marital context reveals important insights into the relationship between family structure and child well-being.

Consensual sadomasochistic sex (BDSM): the roots, the risks, and the distinctions between BDSM and violence

When practiced consensually, sadomasochistic sex is being increasingly accepted as an alternative sexuality. Here I suggest the possible evolutionary roots of the preferences, draw distinctions between violent, abusive and "healthy" practitioners' partnership, provide clear behavioural markers of the respective situations, and underline some specific problems connected to this sexual preference. Some of the problems are well-known in the community of its practitioners, although they have not yet been described in medical nor scientific sources.

Do men's faces really signal heritable immunocompetence?

In the literature on human mate choice, masculine facial morphology is often proposed to be an intersexual signal of heritable immunocompetence, and hence an important component of men's attractiveness. This hypothesis has received considerable research attention, and is increasingly treated as plausible and well supported. In this article, we propose that the strength of the evidence for the immunocompetence hypothesis is somewhat overstated, and that a number of difficulties have been under-acknowledged. Such difficulties include (1) the tentative nature of the evidence regarding masculinity and disease in humans, (2) the complex and uncertain picture emerging from the animal literature on sexual ornaments and immunity, (3) the absence of consistent, cross-cultural support for the predictions of the immunocompetence hypothesis regarding preferences for masculinized stimuli, and (4) evidence that facial masculinity contributes very little, if anything, to overall attractiveness in real men. Furthermore, alternative explanations for patterns of preferences, in particular the proposal that masculinity is primarily an intrasexual signal, have been neglected. We suggest that immunocompetence perspectives on masculinity, whilst appealing in many ways, should still be regarded as speculative, and that other perspectives-and other traits-should be the subject of greater attention for researchers studying human mate preferences.

Polygyny among the Tsimane of Bolivia: an improved method for testing the polygyny-fertility hypothesis

The polygyny-fertility hypothesis states that polygyny is associated with reduced fertility for women and is supported by a large body of literature. This finding is important, because theoretical models of polygyny often differentiate systems based on the degree to which women are forced or willingly choose to enter polygynous marriages. The fact that polygyny tends to be associated with reduced fertility has been presented as evidence that polygyny is often less favourable for women, and that women must, therefore, be pressured into accepting such arrangements. Previous studies, however, have been hampered by the non-random assignment of women into monogamous and polygynous unions (i.e. self-selection), as differences between these groups of women might explain some of the effects. Furthermore, the vast majority of such studies focus on sub-Saharan populations. We address these problems in our analysis of women's fertility in polygynous marriages among the Tsimane of Bolivia. We offer a more robust method for assessing the impact of polygynous marriage on reproductive outcomes by testing for intra-individual fertility effects among first wives as they transition from monogamous to polygynous marriage. We report a significant link between polygyny and reduced fertility when including all cases of polygyny; however, this association disappears when testing only for intra-individual effects.

Polygyny and women's health in rural Mali

Women's social networks and social power are increasingly seen as important factors modulating their health in sub-Saharan Africa. Polygyny, a common marital structure in many societies, mediates important intra-household relationships by requiring both competition and co-operation among co-wives. Using mixed methods, semi-structured questionnaires were administered to 298 women aged 15-84 living in the Kolondiéba region of rural Mali in 1999, and supplemented by detailed interviews with 40 women. Three categories of outcome were explored: illness experience, therapeutic itinerary and social support received. Quantitative data were analysed using regression analysis and qualitative data using a grounded theory approach. In quantitative analyses, controlling for age and household wealth index, senior wives were less likely to be escorted to a healer by their husbands during illness than were junior wives or monogamous women. Polygynous women were also less likely to obtain a treatment for which there was a monetary fee. Fewer than one-third of polygynous women reported the assistance of a co-wife during illness in any given task. In qualitative analyses, women further related varied mechanisms through which polygyny impacted their health trajectories. These ranged from strongly supportive relationships, to jealousy because of unequal health or fertility, bias in emotional and material support provided by husbands, and accusations of wrong-doing and witchcraft. This study highlights the need for more prospective mixed methods analyses to further clarify the impact of polygyny on women's health-related experiences and behaviours in sub-Saharan Africa.

Using community-based research to shape the design and delivery of maternal health services in Northern Nigeria

Maternal mortality ratios in northern Nigeria are among the worst in the world, over 1,000 per 100,000 live births in 2008, with a very low level and quality of maternity services. In 2009, we carried out a study of the reasons for low utilisation of antenatal and delivery care among women with recent pregnancies, and the socio-cultural beliefs and practices that influenced them. The study included a quantitative survey of 6,882 married women, 119 interviews and 95 focus group discussions with community and local government leaders, traditional birth attendants, women who had attended maternity services and health care providers. Only 26% of the women surveyed had received any antenatal care and only 13% delivered in a facility with a skilled birth attendant for their most recent pregnancy. However, those who had had at least one antenatal consultation were 7.6 times more likely to deliver with a skilled birth attendant. Most pregnant women had little or no contact with the health care system for reasons of custom, lack of perceived need, distance, lack of transport, lack of permission, cost and/or unwillingness to see a male doctor. Based on these findings, we designed and implemented an integrated package of interventions that included upgrading antenatal, delivery and emergency obstetric care; providing training, supervision and support for new midwives in primary health centres and hospitals; and providing information to the community about safe pregnancy and delivery and the use of these services.

Women's health in urban Mali: social predictors and health itineraries

Social and marital factors may influence women's health outcomes. This is of particular relevance in sub-Saharan Africa, where women's health indicators lag behind the rest of the world. Our study examines the impact of social mediators of women's health during key events (pregnancy and illness) in urban Mali. In this cross-sectional study, we interviewed 324 women aged 15-80, living in Bamako, the capital city, in 1999. We used mixed quantitative and qualitative methods to obtain detailed histories of pregnancy and illness during specific time periods preceding the survey. We examined the role of marital factors (polygyny, widowhood), social factors (sources of support and scales derived for social network and social power), and household wealth on women's therapeutic itineraries. We compared the sociodemographic characteristics of our sample with those of the 2001 Mali Demographic and Health Survey and used their data on contraception to enrich analyses. We found that most pregnant women delivered in a health center and most women sought medical care during an illness event. Household wealth influenced illness reporting, and financial concerns were obstacles to medical care. Polygyny was associated with lower prevalence of contraceptive use, lower social power, as well as with less support received during pregnancy from women's husbands and in-laws. Widowhood appeared to increase susceptibility to illness, while decreasing resort to biomedical care. Our social composite scores highlighted differences in healthcare utilization in an urban setting with near-uniform access to biomedical care. We validate the utility of locally-derived composite scores, which may provide a deeper understanding into the social mediation of health outcomes for women.

Land inheritance establishes sibling competition for marriage and reproduction in rural Ethiopia

Intergenerational transfer of wealth has been proposed as playing a pivotal role in the evolution of human sibling relationships. Sibling rivalry is assumed to be more marked when offspring compete for limited heritable resources, which are crucial for reproductive success (e.g., land and livestock); whereas in the absence of heritable wealth, related siblings may cooperate. To date, comparative studies undertaken to support this evolutionary assumption have been confounded by other socioecological factors, which vary across populations, e.g., food sharing and intergroup conflict. In this article we explore effects of sibling competition and cooperation for agricultural resources, marriage, and reproduction in one contemporary Ethiopian agropastoralist society. Here recent changes in land tenure policy, altering transfers of land from parents to offspring, present a unique framework to test the importance of intergenerational transfers of wealth in driving sibling competition, while controlling for socioeconomic biases. In households where land is inherited, the number of elder brothers reduces a man's agricultural productivity, marriage, and reproductive success, as resources diminish and competition increases with each additional sibling. Where land is not inherited (for males receiving land directly from the government and all females) older siblings do not have a competitive effect and in some instances may be beneficial. This study has wider implications for the evolution of human family sizes. Recent changes in wealth transfers, which have driven sibling competition, may be contributing to an increased desire for smaller family sizes.

Sex-ratio biasing towards daughters among lower-ranking co-wives in Rwanda

There is considerable debate as to whether human females bias the sex ratio of their offspring as a function of their own condition. We apply the Trivers-Willard prediction-that mothers in poor condition will overproduce daughters-to a novel measure of condition, namely wife rank within a polygynous marriage. Using a large-scale sample of over 95 000 Rwandan mothers, we show that lower-ranking polygynous wives do indeed have significantly more daughters than higher-ranking polygynous wives and monogamously married women. This effect remains when controlling for potential confounds such as maternal age. We discuss these results in reference to previous work on sex-ratio adjustment in humans.

Age at first reproduction and economic change in the context of differing kinship ecologies

Kinship systems which tend to be based on ecologies of subsistence also assign differential power, privilege, and control to human connections that present pathways for manipulation of resource access and transfer. They can be used in this way to channel resource concentrations in women and hence their reproductive value. Thus, strategic female life course trade-offs and their timing are likely to be responsive to changing preferences for qualities in women as economic conditions change. Female life histories are studied in two ethnic groups with differing kinship systems in NE India where the competitive market economy is now being felt by most households. Patrilineal Bengali (599 women) practice patrilocal residence with village exogamy and matrilineal Khasi (656 women) follow matrilocal residence with village endogamy, both also normatively preferring three-generation extended households. These households have helpful senior women and significantly greater income. Age at first reproduction (AFR), achieved adult growth (height) and educational level (greater than 6 years or less) are examined in reproductive women, ages 16-50. In both groups, women residing normatively are older at AFR and taller than women residing nonnormatively. More education is also associated with senior women. Thus, normative residence may place a woman in the best reproductive location, and those with higher reproductive and productive potential are often chosen as households face competitive market conditions. In both groups residing in favorable reproductive locations is associated with a faster pace of fertility among women, as well as lower offspring mortality among Khasi, to compensate for a later start.

Bateman's principles and human sex roles

In 1948, Angus J. Bateman reported a stronger relationship between mating and reproductive success in male fruit flies compared with females, and concluded that selection should universally favour ‘an undiscriminating eagerness in the males and a discriminating passivity in the females’ to obtain mates. The conventional view of promiscuous, undiscriminating males and coy, choosy females has also been applied to our own species. Here, we challenge the view that evolutionary theory prescribes stereotyped sex roles in human beings, firstly by reviewing Bateman's principles and recent sexual selection theory and, secondly, by examining data on mating behaviour and reproductive success in current and historic human populations. We argue that human mating strategies are unlikely to conform to a single universal pattern.

Market forces affect patterns of polygyny in Uganda

Polygynous marriage is generally more beneficial for men than it is for women, although women may choose to marry an already-married man if he is the best alternative available. We use the theory of biological markets to predict that the likelihood of a man marrying polygynously will be a function of the level of resources that he has, the local sex ratio, and the resources that other men in the local population have. Using records of more than 1 million men in 56 districts from the 2002 Ugandan census, we show that polygynously married men are more likely to own land than monogamously married men, that polygynous marriages become more common as the district sex ratio becomes more female biased, that owning land is particularly important when men are abundant in the district, and that a man's owning land most increases the odds of polygyny in districts where few other men own land. Results are discussed with reference to models of the evolution of polygyny.

Polygyny and women's health in sub-Saharan Africa

In this paper we review the literature on the association between polygyny and women's health in sub-Saharan Africa. We argue that polygyny is an example of "co-operative conflict" within households, with likely implications for the vulnerability of polygynous women to illness, and for their access to treatment. We begin with a review of polygyny and then examine vulnerability to sexually transmitted infections (STIs, including HIV) and differential reproductive outcomes. Polygyny is associated with an accelerated transmission of STIs, both because it permits a multiplication of sexual partners and because it correlates with low rates of condom use, poor communication between spouses, and age and power imbalances among other factors. Female fertility is affected by the interplay between marital rank, household status, and cultural norms in polygynous marriages. Finally, we present areas which have received only cursory attention: mental health and a premature, "social" menopause. Although data are scarce, polygyny seems to be associated with higher levels of anxiety and depression, particularly around stressful life events. It is our hope that the examples reviewed here will help build a framework for mixed method quality research, which in turn can inform decision makers on more appropriate, context-dependent health policies.

Polygamy and the use of contraceptives

OBJECTIVES

To compare contraceptive use among women in monogamous and polygamous marriages in Nigeria.

METHODS

Structured questionnaires administered to married women enquired about their marriage type, sociodemographic characteristics, and contraceptive use.

RESULTS

Of the 532 respondents, 33.6% were in polygamous marriages. There was a statistically significant association between monogamy and nonutilization of contraception (P=0.03); however, women in polygamous marriages were more likely not to use contraception when they were older than 35 years, had 4 or more living children, had no male child, had 3 or more female children, or lived in rural areas. There was also a statistically significant association between nonutilization of contraception and number of male children of co-wives (P=0.003), number of female children of co-wives (P=0.05), and use of contraception by co-wives (P=0.002).

CONCLUSION

Polygamy influences contraceptive use and the role of co-wives in this regard merits further study.