Descent, marriage, and residence practices of a 3,800-year-old pastoral community in Central Eurasia.

Our understanding of prehistoric societal organization at the family level is still limited. Here, we generated genome data from 32 individuals from an approximately 3,800-y-old burial mound attributed to the Bronze Age Srubnaya-Alakul cultural tradition at the site of Nepluyevsky, located in the Southern Ural region of Central Eurasia. We found that life expectancy was generally very low, with adult males living on average 8 y longer than females. A total of 35 first-degree, 40 second-degree, and 48 third-degree biological relationships connected 23 of the studied individuals, allowing us to propose a family tree spanning three generations with six brothers at its center. The oldest of these brothers had eight children with two women and the most children overall, whereas the other relationships were monogamous. Notably, related female children above the age of five were completely absent from the site, and adult females were more genetically diverse than males. These results suggest that biological relationships between male siblings played a structural role in society and that descent group membership was based on patrilineality. Women originated from a larger mating network and moved to join the men, with whom they were buried. Finally, the oldest brother likely held a higher social position, which was expressed in terms of fertility.

Lifetime inclusive fitness effects of cooperative polygamy in the acorn woodpecker.

Although over 50 y have passed since W. D. Hamilton articulated kin selection and inclusive fitness as evolutionary explanations for altruistic behavior, quantifying inclusive fitness continues to be challenging. Here, using 30 y of data and two alternative methods, we outline an approach to measure lifetime inclusive fitness effects of cooperative polygamy (mate-sharing or cobreeding) in the cooperatively breeding acorn woodpecker Melanerpes formicivorus. For both sexes, the number of offspring (observed direct fitness) declined while the number of young parented by related cobreeders (observed indirect fitness effect) increased with cobreeding coalition size. Combining these two factors, the observed inclusive fitness effect of cobreeding was greater than breeding singly for males, while the pattern for females depended on whether fitness was age-weighted, as females breeding singly accrued greater fitness at younger ages than cobreeding females. Accounting for the fitness birds would have obtained by breeding singly, however, lifetime inclusive fitness effects declined with coalition size for males, but were greater for females breeding as duos compared to breeding singly, due largely to indirect fitness effects of kin. Our analyses provide a road map for, and demonstrate the importance of, quantifying indirect fitness as a powerful evolutionary force contributing to the costs and benefits of social behaviors.

Exploring the link between household structure and women's household decision-making autonomy in Mauritania.

Governments in sub-Saharan African countries aim to increase married women's household decision-making autonomy as it remains a critical determinant of desirable health behaviours such as healthcare utilisation, antenatal care visits, and safer sex negotiation. However, very few studies explore how household structure (i.e., monogamous or polygamous) is associated with married women's household decision-making autonomy. Our paper seeks to address this gap. Using the 2019-20 Mauritania Demographic and Health Survey, a nationally representative dataset, and applying logistic regression analysis, we explore how married women's household structure is associated with their household decision-making autonomy. We find that 9% of married women are in polygamous marriages, while 63% and 65% are involved in decision-making about their health and large household purchases, respectively. Additionally, 76% and 56% are involved in decision-making about visiting family or relatives and household expenditures. After accounting for socio-economic and demographic factors, we find that compared to women from monogamous households, those from polygamous households are less likely to participate in decision-making about their health (OR=0.65, p < 0.001), making large household purchases (OR=0.65, p < 0.001), visiting family or relatives (OR=0.72, p < 0.001), and household expenditure (OR=0.58, p < 0.001). Based on our findings, we recommend the urgent need to review and re-evaluate policies and approaches seeking to promote gender equality and women's autonomy in Mauritania. Specifically, it may be critical for intervention programmes to work around reducing power imbalances in polygamous household structures that continue to impact married women's household decision-making autonomy adversely. Such interventions should centre married women's socio-economic status as a central component of their empowerment strategies in Mauritania.

Tighter Constraints of Multi-Qubit Entanglement in Terms of Nonconvex Entanglement Measures LCREN and LCRENoA.

The monogamy property of entanglement is an intriguing feature of multipartite quantum entanglement. Most entanglement measures satisfying the monogamy inequality have turned out to be convex. Whether nonconvex entanglement measures obey the monogamy inequalities remains less known at present. As a well-known measure of entanglement, the logarithmic negativity is not convex. We elucidate the constraints of multi-qubit entanglement based on the logarithmic convex-roof extended negativity (LCREN) and the logarithmic convex-roof extended negativity of assistance (LCRENoA). Using the Hamming weight derived from the binary vector associated with the distribution of subsystems, we establish monogamy inequalities for multi-qubit entanglement in terms of the αth-power (α≥4ln2) of LCREN, and polygamy inequalities utilizing the αth-power (0≤α≤2) of LCRENoA. We demonstrate that these inequalities give rise to tighter constraints than the existing ones. Furthermore, our monogamy inequalities are shown to remain valid for the high-dimensional states that violate the CKW monogamy inequality. Detailed examples are presented to illustrate the effectiveness of our results in characterizing the multipartite entanglement distributions.

Extra-pair paternity and sexual dimorphism in birds.

Differences in the strength of sexual selection between males and females can lead to sexual dimorphism. Extra-pair paternity (EPP) can increase the variance in male reproductive success and hence the opportunity for sexual selection. Previous research on birds suggests that EPP drives the evolution of dimorphism in plumage colour and in body size. Because EPP increases the intensity of sexual selection in males, it should lead to increased dimorphism in species with larger or more colourful males, but decreased dimorphism in species with larger or more colourful females. We explored the covariation between EPP and sexual dimorphism in wing length and plumage colouration in 401 bird species, while controlling for other, potentially confounding variables. Wing length dimorphism was associated positively with the frequency of EPP, but also with social polygamy, sex bias in parental behaviour and body size and negatively with migration distance. The frequency of EPP was the only predictor of plumage colour dimorphism. In support of our prediction, high EPP levels were associated with sexual dichromatism, positively in species in which males are more colourful and negatively in those in which females are more colourful. Contrary to our prediction, high EPP rates were associated with increased wing length dimorphism in species with both male- and female-biased dimorphism. The results support a role for EPP in the evolution of both size and plumage colour dimorphism. The two forms of dimorphism were weakly correlated and predicted by different reproductive, social and life-history traits, suggesting an independent evolution.

Mechanisms that can cause population decline under heavily skewed male-biased adult sex ratios.

While adult sex ratio (ASR) is a crucial component for population management, there is still a limited understanding of how its fluctuation affects population dynamics. To demonstrate mechanisms that hinder population growth under a biased ASR, we examined changes in reproductive success with ASR using a decapod crustacean exposed to female-selective harvesting. We examined the effect of ASR on the spawning success of females. A laboratory experiment showed that the number of eggs carried by females decreased as the proportion of males in the mating groups increased. Although the same result was not observed in data collected over 25 years in the wild, the negative effect of ASR was suggested when success in carrying eggs was considered as a spawning success. These results indicate that a surplus of males results in females failing to carry eggs, probably due to sexual coercion, and the negative effect of ASR can be detected at the population level only when the bias increases because failure in spawning success occurs in part of population. We experimentally examined how male-biased sex ratios affected the maintenance of genetic diversity in a population. The diversity of paternity in a clutch increased with the number of candidate fathers. However, over 50% of a clutch was fertilised by a single male regardless of the sex ratio, and the degree of diversity was less than half of the highest diversity expected in each mating group. We also experimentally examined the mating ability of males during the breeding season. The experiment showed that multiple mating by males could not compensate for the risk that their genotypes would be lost when multiple males competed for one female. These results suggest that a male-biased ASR could trigger a decline of genetic diversity in a population. We show that ASR skewed by female-selective harvesting decreases reproductive success not only of males that have few mating opportunities but also of females. We discuss that we may still underestimate the significance of ASR on population persistence due to the difficulty of revealing the effect of ASR.

Polygamy and safe sex negotiation among married women: evidence from Cameroon.

BACKGROUND: Research indicates that women in polygamous relationships may be exposed to unique sexual and reproductive health challenges. However, there are very few studies that examine whether polygamy is associated with safe sex negotiation among married women in sub-Saharan Africa, including Cameroon. METHODS: Using the 2018 Cameroon Demographic and Health Survey, we apply logistic regression analysis to compare two indicators of safe sex negotiation (i.e., the ability to ask for condom use and refuse sex against their partner) between polygamous (n = 1,628) and monogamous (n = 5,686) women aged 15-49 years old. RESULTS: We find that 67% and 50% of married women can ask for condom use and refuse sex against their partner, respectively. Multivariate analysis further reveals that women in polygamous relationships are less likely to report they can ask for condom use (OR = 0.71, p < 0.001) and refuse sex (OR = 0.64, p < 0.001) in comparison to their monogamous counterparts. CONCLUSIONS: Our analysis found that in Cameroon, women in polygamous relationships, Muslim women, married women with inadequate HIV knowledge, those who had never been tested for HIV and women with lower socioeconomic status are less likely to negotiate for safe sex. Based on these findings, we discuss several implications for policymakers, including the establishment of a comprehensive family planning educational program and the deployment of community health workers to disseminate educational initiatives pertaining to safe sex negotiation to community members.

Cryptic female choice within individual males - A neglected component of the postmating sexual selection?

Cryptic female choice (CFC) is commonly assumed to act only in polyandrous mating systems, which allows females to bias fertilization towards the sperm of particular males. However, accumulated evidence has demonstrated that sperm show significant phenotypic and genotypic variation also within single ejaculates, which have important consequences for offspring phenotype and fitness. Here, I argue that these neglected sources of intra-male sperm variation often allow CFC to act also within individual males and facilitate fertilization bias towards genetically compatible (or otherwise preferred) sperm haplotypes. In this article, I explain prerequisites for within-male CFC, the criteria for demonstrating it and summarize accumulated evidence for this emerging selection process. Then, I evaluate prevalence of within-male CFC and review its potential evolutionary consequences. The aim of this article is to broaden the current definition of CFC by demonstrating that CFC has potential to act in all mating systems, in both internally and externally fertilizing species. Incorporation of the within-male CFC concept into the current models of sexual selection may provide novel insights into the deeper understanding of selective factors driving the evolution of mating systems and reproductive proteins. Finally, within-male CFC towards particular sperm haplotypes may increase our understanding of non-Mendelian inheritance.

On Male Harm: How It Is Measured and How It Evolves in Different Environments.

AbstractMales can harm the females that they interact with, but populations and species widely vary in the occurrence and extent of harm. We consider the merits and limitations of two common approaches to investigating male harm and apply these to an experimental study of divergence in harm. Different physical environments can affect how the sexes interact, causing plastic and/or evolved changes in harm. If harmful male phenotypes are less likely to evolve in situations where females have more control over sexual interactions, populations evolving in environments in which females have greater control should have less harmful males. We test this idea using experimental populations of Drosophila melanogaster that have evolved in either of two environments that vary in the extent to which females can avoid males or in a third environment without mate competition (i.e., enforced monogamy). We demonstrate an evolved reduction in harm in the absence of mate competition and also in a mate competition environment in which females have greater control. We also show a plastic effect in that otherwise harmful males are no longer so when tested in the environment in which females have greater control. Our results reveal the different perspectives provided by the two methods of studying harm.

Psychological impact of polygamous marriage on women and children: a systematic review and meta-analysis.

BACKGROUND: Over the last two decades, there has been significant growth in public, political, and academic awareness of polygamy. Polygamous families have distinct household problems, usually stemming from jealousy between co-wives over the husband's affections and resources. This study aimed to ascertain the psychological impact of polygamous marriage on women and children worldwide. METHODS: A systematic search was performed in MEDLINE (PubMed), Scopus, CINAHL (EBSCOhost), Google Scholar, and ProQuest using search terms such as "marriage" and "polygamy." Studies published from the inception of the respective databases until April 2021 were retrieved to assess their eligibility for inclusion in this study. The Joanna Briggs Institute Critical Appraisal Checklist was used for data extraction and the quality assessment of the included studies. The generic inverse variance and odds ratios with 95% confidence intervals (CI) were calculated using RevMan software. RESULTS: There were 24 studies fulfilling the eligibility criteria, and 23 studies had a low risk of bias. The pooled meta-analysis showed women in polygamous marriages had a 2.25 (95% CI: 1.20, 4.20) higher chance of experiencing depression than in monogamous marriages. Children with polygamous parents had a significantly higher Global Severity Index with a mean difference of 0.21 (95% CI: 0.10, 0.33) than those with monogamous parents. CONCLUSIONS: The psychological impact of polygamous marriage on women and children was found to be relatively higher than monogamous marriage. Awareness of the proper practices for polygamy should be strengthened so that its adverse effects can be minimized. The agencies involved in polygamous practices should broaden and enhance their understanding of the correct practice of polygamy.

The prevalence of premature ejaculation and its relationship with polygamous men: a cross-sectional observational study at a tertiary hospital in Somalia.

BACKGROUND: Premature ejaculation (PE) is the most common and prevalent sexual disorder among men. To the best of our knowledge, this is the first study aimed at evaluating the relationship of PE among polygamous men. METHOD: Over a 1-year period, a cross-sectional observational study was carried out among 202 married men who visited the urology polyclinic due to different clinical conditions and contributed by completing a standardized structured questionnaire regarding their sociodemographic data, as well as sexual and past medical history. RESULTS: In our study, the prevalence of PE was 37.1%; half of the monogamous men (50%) complained of PE, while 22% of men with two wives, 20% of men with three wives, and 12% of men with four wives complained of PE (p < 0.0001, 95% CI 0.122-1.920). Seventy percent of erectile dysfunction (ED) patients had PE concurrence (p < 0.0001, 95% CI 0.057-5.543). Regarding frequency of sexual intercourse, 48% of patients who complained of PE performed sexual intercourse less than two times/week, while two-thirds of the participants who did not complain of PE had sexual intercourse two to four times/week (p < 0.0001, 95% CI 0.203-0.568). Among the men who reported ED, 42% had one wife, 21.5% had two wives, 40% had three wives, and 12.5% had four wives (p < 0.029, 95% CI 0.417-0.962). CONCLUSIONS: We report that polygamous men have a lower incidence of premature ejaculation and higher sexual satisfaction than monogamous men. There is a significant association between ED and PE, showing a complex and bidirectional relationship between the two conditions. The new taxonomic entity called loss of control of erection and ejaculation (LCEE) views the two sexual symptoms as deeply interrelated. The study results indicate that a sexual intercourse frequency of two or more times per week significantly lowers the risk of PE.

Prevalence of mental health problems in women in polygamous versus monogamous marriages: a systematic review and meta-analysis.

While some studies suggest different mental health outcomes among women in polygamous versus monogamous marriages, no published systematic review or meta-analysis has analyzed the relevant research literature. This article aims to review the evidence of marriage types (i.e., polygamous and monogamous marriages) and differences in the prevalence of mental health issues. Eleven electronic databases, along with further identified references lists, were searched. Thirteen studies met the inclusion criteria. They included 3166 participants, and 986 women were in a polygamous marriage. All studies were rated for quality and were tested for publication bias. Meta-analyses were conducted on the five symptoms to assess for the effect of marriage type. The studies indicate a significant association of marriage type with psychological symptoms. The meta-analysis indicates that women in polygamous marriage had worsened mental health as compared with women in monogamous marriages. The weighted mean differences with 95% confidence intervals were somatization 0.53, 0.44-0.63; obsession-compulsion 0.35, 0.14-0.56; interpersonal sensitivity 0.42, 0.12-0.73; depression 0.41, 0.15-0.67; anxiety 0.41, 0.15-0.68; hostility = 0.47, 0.28-0.66; phobic anxiety 0.39, 0.17-0.61; paranoid ideation 0.35, 0.24-0.47; psychoticism 0.41, 0.23, 0.59; and Global Severity Index (GSI) 0.43, 0.25-0.60. A higher self-esteem and life satisfaction among women in polygamous marriages and statistically superior family functioning among women in monogamous marriages were also found. However, there was no statistically significant difference between the marital satisfaction of women in polygamous versus monogamous marriages. Results are consistent with the existing research on the prevalence of mental health issues among women in polygamous marriages. Nonetheless, these women were found to have elevated self-esteem and life satisfaction than women in monogamous marriages. Directions for future research are indicated.

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.

Fitness benefits of male dominance behaviours depend on the degree of individual inbreeding in a polyandrous lizard.

In polyandrous species, sexual selection extends beyond mating competition to selection for egg fertilization. As a result, the degree to which factors influencing mating success impact overall reproductive success becomes variable. Here, we used a longitudinal behavioural and genetic dataset for a population of eastern water dragons (Intellagama lesueurii) to investigate the degree to which male dominance, a pre-mating selection trait, influences overall reproductive success, measured as the number of surviving offspring. Moreover, we examine the interactive effects with a genetic trait, individual inbreeding, known to influence the reproductive success of males in this species. We found fitness benefits of male dominance, measured as body size and frequency of dominance behaviours displayed. However, individuals' propensity to display dominance behaviours had mixed effects, depending on the degree of inbreeding. While inbred males benefited from frequent displays, highly outbred males exhibited better reproductive outputs when displaying to a lesser extent. Given that outbred males have enhanced reproductive success in this species, the costs of displaying dominance behaviours may outweigh the benefits. Overall, our results demonstrate the fitness benefits of dominance in a polyandrous lizard, and suggest that these are modulated by an independent genetic trait. Our results may contribute to explaining the presence of alternative mating tactics in this species, owing to the variability in net fitness benefits of dominance. Our findings also reveal the challenges associated with investigating fitness traits in isolation, which may undermine the validity of results when important interactions are ignored.

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.

First record of the mating behaviour of the spotted surubim Pseudoplatystoma corruscans in the Uruguay River.

The spotted surubim Pseudoplatystoma corruscans is a large migratory catfish native to the La Plata and San Francisco basins. Nonetheless, its reproductive dynamics and behaviour remain poorly understood. This brief note provides the first record of the mating behaviour of P. corruscans in natural conditions. This behaviour was observed in the main channel of the Middle Uruguay River (Brazil). A school of approximately 25 fish, 5 females (with protruding abdomen and larger body size) and 20 males, were followed and videotaped. The largest female led the school, followed by other fish. Some males disputed repeatedly the posterior region of the females, whereas other males continuously repelled them. Eventually, some males, apparently exhausted, floated belly up. During this event, males were in a state of pronounced agitation, and some had abrasions in the head. Polygamy characterized the mating behaviour of P. corruscans.

Male age and its association with reproductive traits in captive and wild house sparrows.

Evolutionary theory predicts that females seek extra-pair fertilizations from high-quality males. In socially monogamous bird species, it is often old males that are most successful in extra-pair fertilizations. Adaptive models of female extra-pair mate choice suggest that old males may produce offspring of higher genetic quality than young males because they have proven their survivability. However, old males are also more likely to show signs of reproductive senescence, such as reduced sperm quality. To better understand why old males account for a disproportionally large number of extra-pair offspring and what the consequences of mating with old males are, we compared several sperm traits of both captive and wild house sparrows, Passer domesticus. Sperm morphological traits and cloacal protuberance volume (a proxy for sperm load) of old and young males did not differ substantially. However, old males delivered almost three times more sperm to the female's egg than young males. We discuss the possibility of a post-copulatory advantage for old over young males and the consequences for females mated with old males.

Women with infertility complying with and resisting polygyny: an explorative qualitative study in urban Gambia.

BACKGROUND: In many low-and middle-income countries women with infertility are often in polygynous marriages. From a human and women's rights perspective, the practice of polygyny is commonly understood as harmful. Studies indicate that polygyny aggravates negative life circumstances of women with infertility with respect to their health and social well-being. The purpose of this qualitative study is to explore how women with infertility experience polygyny and to understand their decision-making regarding these marriages. METHODS: An explorative qualitative study was conducted among women with infertility in the urban communities of the West Coast region of The Gambia using in-depth interviews (30). Data analysis involved an emergent and partially inductive thematic framework and was carried out using NVivo 11. RESULTS: With the exception of some women with infertility who described positive experiences within polygynous marriages, most women emphasised conflicts that exist within polygynous households and reported financial and emotional difficulties. Thematic analysis identified several strategies of women with infertility to cope with and resist polygynous marriages, including overcoming childlessness, addressing conflict, spending time outside the compound, looking for social support, kanyaleng kafoolu, living separately and initiating divorce. Moreover, the experiences and decision-making power of women with infertility when it comes to polygynous marriages was found to be closely related to their socio-demographic background. CONCLUSION: This work highlights how women with infertility in polygynous marriages are in a precarious situation in urban Gambia. Women utilize a mix of compliance, coping and resistance strategies to navigate the challenges of polygynous marriages in a structurally constraining context.

Polygamy or subdioecy? The impact of diallelic self-incompatibility on the sexual system in Fraxinus excelsior (Oleaceae).

How flowering plants have recurrently evolved from hermaphroditism to separate sexes (dioecy) is a central question in evolutionary biology. Here, we investigate whether diallelic self-incompatibility (DSI) is associated with sexual specialization in the polygamous common ash (Fraxinus excelsior), which would ultimately facilitate the evolution towards dioecy. Using interspecific crosses, we provide evidence of strong relationships between the DSI system and sexual phenotype. The reproductive system in F. excelsior that was previously viewed as polygamy (co-occurrence of unisexuals and hermaphrodites with varying degrees of allocation to the male and female functions) and thus appears to actually behave as a subdioecious system. Hermaphrodites and females belong to one SI group and functionally reproduce as females, whereas males and male-biased hermaphrodites belong to the other SI group and are functionally males. Our results offer an alternative mechanism for the evolution of sexual specialization in flowering plants.

Socio-demographic and behavioural profile of women in polygamous relationships in South Africa: a retrospective analysis of the 2002 population-based household survey data.

BACKGROUND: The prevalence and effect of polygamous relationships may have serious reproductive and /or health consequences for women. In South Africa, unlike in other sub-Saharan countries, no nationwide survey has investigated polygamy except for the 2002 HIV/AIDS population-based household survey. The aim of this study was to profile socio-demographic and behavioural characteristics associated with women in polygamous relationships in South Africa using the 2002 survey data. METHODS: The survey data were collected using a multi-stage stratified cluster randomised sampling design. Bivariate and multivariate logistic regression models were used to assess the relationship between polygamy, and selected socio-demographic and behavioural factors. RESULTS: Of 1437 women who responded to the question on polygamy, 8.3% reported being in a polygamous marriage. Women in polygamous marriages were significantly less likely to have tertiary education [OR = 0.03(95% CI: 0.00-0.28), p = 0.003], to have money for food and clothes [OR = 0.12 (95% CI: 0.06-0.27), p < 0.001], to have a sexual partner five years younger [OR = 0.10 (95% CI: 0.01-0.94), p = 0.044] or sexual partner within 5 years older or younger [OR = 0.35 (95% CI: 0.13-0.991), p = 0.032]. They were also significantly more likely to have two or more sexual partners [OR = 20.42 (95% CI: 1.10-379.89), p = 0.043]. CONCLUSION: The finding that polygamy is associated with uneducated and women of low economic means, who have relationships with older men and multiple sexual partners warrants further attention. Contemporary studies on polygamy are needed in South Africa.