Marriages between blood relatives—also known as consanguineous unions—are widespread in North Africa, Central and West Asia, and South Asia. Researchers have suggested that consanguinity has adverse effects on child development, but assessing its impact is not straightforward, as the decision to marry a relative might be endogenous to other socio-economic factors. Using a unique data set collected in rural Pakistan, this paper assesses the extent to which consanguinity is linked to children’s cognitive and physical development. It exploits grandfathers’ land ownership (current and past) and maternal grandparent mortality to identify the effect of endogenous consanguinity on child development. Children born into consanguineous unions have lower cognitive scores, lower height-for-age, and a higher likelihood of being severely stunted. More importantly, adverse effects are greater after accounting for the endogeneity of consanguinity, suggesting that impacts on child development are substantial, and likely to be larger than suggested in previous studies.

中文翻译：

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血缘关系是儿童发育的障碍吗？

血亲之间的婚姻（也称为近亲婚姻）在北非，中亚和西亚以及南亚很普遍。研究人员认为，血缘关系对儿童发育有不利影响，但评估其影响并非易事，因为与亲戚结婚的决定可能是其他社会经济因素的内生因素。利用巴基斯坦农村地区收集的独特数据集，本文评估了血缘关系与儿童的认知和身体发育相关的程度。它利用祖父的土地所有权（当前和过去）和母亲祖父母的死亡率来确定内源性血缘关系对儿童发育的影响。血缘结合的孩子的认知得分较低，年龄高度较低，严重发育不良的可能性更高。