Author: Caroline Uggla Having a mother who is married to a man who has at least one other wife – that is, polygynously married – can be better than having parents who are married monogamously for some children in Ethiopia. At least for outcomes such as child survival, education and marriage. But how children fare depends on the wife rank of the mother, and outcomes vary for sons and daughters.
Polygamy is the marriage practice where men are allowed to take multiple wives. It is much more common than many people believe, and exists in about 80% of human societies across the globe, but is common especially in West and East Africa and in south America.
Whether polygyny is a harmful cultural practice has generated some debate recently and is of high policy interest. Why men should favour polygyny is pretty clear – they can both have more children, and get more labour participation from multiple wives. But the benefits to women are less evident.
With several women and their children sharing one husband, it has been argued that polygyny has harmful consequences for women and children, through poorer health and child survival. This has prompted anthropologists to ask why women, or their parents on their behalf, should accept to marry a man who is already married?
Our study is based on data we collected through household surveys from circa 1200 Arsi Oromo women. The Arsi Oromo are agropastoralists who live in southwestern Ethiopia and primarily rely on cattle rearing with some cultivation of sorgum and maize. We asked about various outcomes related to health, education and marriage for their ~ 6200 children.
We wanted to test whether sons and daughters fared differently, and if there was a son bias in polygynous households. Previous studies have mostly looked at all children together, which means that any costs to one group of children can be concealed. In polygynous households, sons who get investment from parents might themselves grow up to become polygynyous, and generate more grandchildren. But because of female reproduction, a daughter can only have a given number of children, regardless of how much her parents invest in her.
Our results show that children of both polygynous first wives and second order wives have some advantages over monogamous wives. But we can also show that these advantages are a little more complex than previously thought. We could not detect any overall son bias, but the outcomes were sex-specific. This is what we found, in brief:
- Polygynous first wives had the same level of child survival as monogamous women, but children of first wives did better than children of monogamous women in both these later life outcomes.
- Polygynous second order wives had lower child survival compared to monogamous wives. But, if the children of second wives survived the critical first 5 years of life, their daughters had a lower age at first marriage, and the boys had the same level of education as boys of monogamous mothers.
To marry young is important for Arsi Oromo girls, because the most desirable marriage partners are married off younger and their parents receive a higher bride price. These women who marry younger have better health later in life, so it may not be categorically harmful to marry younger than 18 years of age among the Arsi Oromo. For boys, to have some education is marker of status and increases marriageability, even if most will never have a job that requires higher education.
Something that is also novel for this study and rare in the anthropological literature where sample sizes are often small, is that we control statistically for unmeasured differences between mothers, in a so called multilevel model where children are clustered within mothers. This means that these results are more robust than some prior anthropological studies which have been purporting that polygyny is associated with harmful outcomes for women and children.
It is possible that being born to a polygynous mother means that higher social status and prestige of being married to a high status man leads to advantages also in the next generation. Among the Arsi Oromo, the woman who gives birth to the first son in a union, often the first wife, receives high social status within the community, benefits which might trickle down to her children. While there might be conflict between cowives, anthropological evidence also emphasies cooperative benefits when burdens of childcare and household tasks can be shared among cowives.
It is not unlikely that some individuals are more likely to become polygynous because of their perceived attractiveness, personality, or cognitive abilities but that we lack data on here. To test this interpretation, data from small scale populations over several decades is required, before and after entry into marriage, an important next step for future studies.
The results cannot be explained by the fact that rich men can afford to take multiple wives, and are more likely to have sons who go to school for longer, and daughters who marry younger. The Arsi Oromo have relatively low wealth inequality because of governmental land redistribution reforms. We also controlled for the mother’s level of education in these models, and so any associations cannot be explained by monogamous women being more ”modern” and highly educated.
To be born to a first wife is clearly beneficial. But why marry a married man? Our results show that even second order wives have some advantages over monogamous women in terms of the later life outcomes of their children. These results make it more difficult to state that polygyny is a harmful cultural practice.
For policy makers, it is important to understand the context in which polygyny takes place. We do not necessarily anticipate the same outcomes of polygyny in all societies. But, overall, if women have autonomy over their marital decisions, harmful consequences of polygyny are not expected. Thus, banishing polygyny could do more harm than good for populations depending what social structures are in place.
Are wives and daughters disadvantaged in polygynous housholds? A case study of the Arsi Oromo of Ethiopia, by Caroline Uggla, Eshetu Gurmu and Mhairi Gibson in Evolution and Human Behavior.