"We Shall Overcome!" | A Professional Journey
Why Do So Many People in Poor
Countries Marry Their First Cousin?
The topic of marriage between cousins usually produces a response among Americans that varies between a facial cringe and an “Eeeww!” Most Americans are surprised to discover that over 50 percent of all marriages in Pakistan are between first cousins.
The topic of marriage between cousins usually produces a response among Americans that varies between a facial cringe and an “Eeeww!” Most Americans are surprised to discover that over 50 percent of all marriages in Pakistan are between first cousins.
Geneticists have long pointed out the biological risks to the offspring of first cousin unions, and if we are to believe the numbers produced by population geneticists, there is a 4.4 percentage point increased risk of mortality for such children. Even in a high infant-mortality environment like Pakistan, this increases the baseline risk of infant death by as much as 50 percent. This makes it quite puzzling that so many people in the developing world would continue to marry their biological relatives, a practice referred to as consanguinity. The high rates of reported consanguinity and of mortality make it equally puzzling why Pakistan has not already experienced some sort of genetic implosion.
Pointing to a lack of understanding of the biological risks is by itself not a satisfactory answer, since even cultures with no knowledge of genetics could have probabilistically observed the greater incidence of mortality or genetic deformities among consanguineous progeny over centuries, and could have reacted in response. Indeed, many Western societies and the Roman Catholic and Orthodox churches long ago developed social prejudices, religious taboos, or laws to prohibit marriages between close relatives. We therefore might expect similar norms to develop across all cultures, but somehow they have not.
These and other puzzles led a research team comprised of Dr. Mushfiq Mobarak and Dr. Murat Iyigun from the CU-Boulder Department of Economics, Dr. Nizam Khan from the CU-Boulder Institute of Behavioral Science, and Dr. Alan Bittles from the Centre for Human Genetics in Perth, Australia, to ask the following question in a project that is funded by the U.S. National Science Foundation:
Are there countervailing socioeconomic benefits of consanguineous unions that, despite their biological risks, help to sustain the incidence of such marriages?
Understanding both the reasons behind consanguinity and its true biological risks are important, especially in view of the large influx of immigrants into the U.S. fromregions of the world where this practice is common. Recently, a British member of Parliament representing Bradford, an area where many immigrants of Pakistani origin reside, proposed a ban on consanguineous marriage citing the possibility that the presumed genetic diseases associated with the practice have the potential to stress the British medical system. Without a better understanding of the socioeconomic origins of this practice, it is not easy to judge whether such a ban is called for, and also, it may not be an enforceable ban if the community has strong enough reasons to continue the practice. This research project aims to inform such policy debates by gaining a deeper understanding of the social, economic, and biological forces at play in the decision to marry a biological relative.
Also, in spite of the reported numbers on the adverse effects of consanguinity, it is actually not clear how large the negative effects really are. This is because all the numbers that are currently cited are based on comparisons of the health of children of first cousin unions against children from other families. Such raw comparisons do not take into account the possibility that the families selecting into consanguineous unions may have other characteristics that independently predispose them toward higher mortality and morbidity rates. For example, if families whose daughters are more likely to marry a relative have, on average, less understanding of proper nutrition and sanitation practices, then their mortality/ morbidity rates may be amplified relative to other families, and if we fail to take this into account, we could wrongly attribute the adverse health effect to consanguinity.
Using data collected in rural Bangladesh, this research project explicitly recognizes the problem family characteristics that are independent of consanguinity poses for measuring the adverse effects of consanguinity. The availability or unavailability of a suitable cousin for marriage provides a statistical control that allows the researchers to separately measure the effects of family characteristics and consanguinity on mortality/morbidity rates.
Using data collected in rural Bangladesh, this research project explicitly recognizes the problem family characteristics that are independent of consanguinity poses for measuring the adverse effects of consanguinity. The availability or unavailability of a suitable cousin for marriage provides a statistical control that allows the researchers to separately measure the effects of family characteristics and consanguinity on mortality/morbidity rates.