Quantifying the Prospects for Consanguineous Marriage when Fertility Declines

Stuart A. Basten, University of Oxford
Bilal Barakat, Vienna Institute of Demography

Consanguinity is widely practiced and even socially encouraged in many countries. Numerous studies have stated that the practise cannot continue at present levels and in present form in the face of fertility transition. However, the future impact of fertility transition on availability of cousins to marry has yet been quantified. We perform a simulation exercise using past and projected NRRs derived from the UN. We calculate the average number of cousins of the opposite sex as a function of the average number of children; the average probability for an individual to have at least one eligible paternal cousin of the opposite sex and conclude with an examination of constraints on consanguineous marriage in selected countries under different fertility assumptions. Current and projected fertility levels in Middle Eastern countries create challenging constraints on the custom once today's birth cohorts reach marriageable age.