Journal of Biosocial Science (2019), 51: 3, 418–435 doi:10.1017/S0021932018000275 ARTICLE Estimating the health and socioeconomic effects of cousin marriage in South Asia A. Mushfiq Mobarak 1,2 * , Theresa Chaudhry 3 , Julia Brown 4 , Tetyana Zelenska 5 , M. Nizam Khan 6 , Shamyla Chaudry 3 , Rana Abdul Wajid 3 , Alan H. Bittles 7,8 and Steven Li 9 1 School of Management, Yale University, New Haven, USA, 2 Department of Economics, Deakin University, Melbourne, Australia, 3 Lahore School of Economics, Lahore, Pakistan, 4 University of Maryland, College Park, MD, USA, 5 Landesa (Rural Development Institute), Seattle, WA, USA, 6 ICF International, Rockville, MD, USA, 7 Centre for Comparative Genomics, Murdoch University, Australia, 8 School of Medical and Health Sciences, Edith Cowan University, Perth, Australia and 9 Facebook, Seattle, WA, USA *Corresponding author. Email: ahmed.mobarak@yale.edu (Received 26 February 2018; revised 18 June 2018; accepted 26 July 2018; First published online 5 October 2018) Abstract The effects of marriage between biological relatives on the incidence of childhood genetic illness and mortality are of major policy significance, as rates of consanguinity exceed 50% in various countries. Empirical research on this question is complicated by the fact that consanguinity is often correlated with poverty and other unobserved characteristics of households, which may have independent effects on mortality. This study has developed an instrumental variables empirical strategy to re-examine this question, based on the concept that the availability of unmarried cousins of the opposite gender at the time of marriage creates quasi-random variation in the propensity to marry consanguineously. Using primary data collected in Bangladesh in 2006–07 and Pakistan in 2009–10, the study found that previous estimates of the impact of consanguinity on child health were biased and falsely precise. The study also empirically investigated the social and economic causes of consanguinity (including marital quality) and concludes that marrying a cousin can have positive economic effects for one’s natal family, by allowing deferral of dowry payments until after marriage. Keywords: Consanguinity; Marriage and Mate Selection; Medical and Public Health Genetics Introduction While marriage between people who are genetically related is relatively uncommon in most Western societies, in many parts of Asia and Africa and among emigrants from these regions 20– 50 + % of marriages are consanguineous, defined as marriage between individuals related as second cousins or closer and equivalent to a coefficient of inbreeding (F) ≥0.0156 (Bittles & Black, 2010). Concern over the potential public health implications of marriages between bio- logical relatives has spurred research into the incidence of childhood mortality and genetic illness in the offspring of such unions. This research has important policy implications, as legislation curtailing consanguineous marriage may conflict with traditional beliefs. Parents who arrange consanguineous marriages for their children may also reap socioeconomic benefits, such as delayed dowry payments or better treatment of their daughters by their husbands’ family. Genetic research indicates that marriage to a close biological relative should result in a higher incidence of genetically related illness in their offspring due to the expression of rare, detrimental, recessive genes (Bittles & Neel, 1994; Hamamy et al., 2011; Bittles, 2012; Sheridan et al., 2013; Bishop et al., 2017). Since first cousins co-inherit 12.5% of their genes from a common ancestor, the risk that both carry identical copies of a detrimental gene – and therefore the risk of that gene © Cambridge University Press, 2018. https://www.cambridge.org/core/terms. https://doi.org/10.1017/S0021932018000275 Downloaded from https://www.cambridge.org/core. Yale University Library, on 14 Apr 2019 at 16:29:57, subject to the Cambridge Core terms of use, available at