Washington: Polygyny - where one husband has more than one wife - may lead to greater health and wealth for women and their children in some circumstances, according to a new study that may raise eyebrows.
Polygyny is decried by the United Nations Human Rights Committee and women's rights organisations as discriminatory to women.
The new study of polygyny in Tanzania, however, found that the practice of sharing a husband may, in some circumstances, lead to greater health and wealth for women and their children.
Researchers at University of California, Davis in US compared polygynous and monogamous households in 56 villages in northern Tanzania, where polygyny is widespread among certain ethnic groups, including the Maasai.
When comparing households within individual villages, polygynous households often had better access to food and healthier children. Polygynous households also owned more cattle and farmed more land than monogamous households.
The findings support evolutionary anthropological accounts of marriage indicating that polygyny can be in a woman's strategic interest when women depend on men for resources, researchers said in the study published in the Proceedings of the National Academy of Sciences journal.
"If you have a choice of a guy who has 180 cows, lots of land and other wives, it might be better for you to marry him rather than a guy who has no wives, three cows and one acre," said researcher Monique Borgerhoff Mulder from UC Davis.
Consistent with prior research, the study found that polygyny was associated with low food security and poor child health when looking at data across all villages.
However, this pattern was accounted for by the tendency of polygyny to be most common in ecologically vulnerable and marginalised ethnic groups.
This error of interpretation is known as the "ecological fallacy," and flaws all previous analyses of large data sets like the Demographic and Health Surveys, researchers said.
"Our study suggests that highly polygynous, predominantly Maasai, villages do poorly not because of polygyny, but because of vulnerability to drought, low service provision and broader socio-political disadvantages," said lead author David Lawson at the London School of Hygiene and Tropical Medicine.
The researchers highlighted the importance of local context in studying the health implications of cultural practices, and suggest that in some settings, prohibiting polygyny could be disadvantageous to women by restricting their marriage options.
The study is limited to food security and health, and cannot tell us about the wider potential for polygyny to cause harm, the researchers said.
They also noted that polygyny was only associated with superior outcomes when fathers and children were co-resident - outcomes for other polygynously-married women were indistinguishable from those of monogamous women.
