Factors Influencing Consanguineous Marriage Prevalence

Key Insight

Globally, the prevalence of consanguineous marriages varies significantly, with regions like North Africa, the Middle East, and parts of South Asia exhibiting high rates, where 20 to 50 percent of marriages are between partners descended from a recent common ancestor. Pakistan, for example, sees first-cousin marriages account for at least 50 percent of all unions, while in the Americas, Europe, and North and East Asia, these marriages are under 5 percent. This disparity raises questions about the underlying causes.

While some religions explicitly permit cousin marriages, such as Islam (as seen in the Qur'an and Prophet Muhammad's own marriages), and some forms are allowed in Hinduism (especially in South India where 30 percent of marriages are first-cousin or uncle-niece unions), religion is unlikely to be the sole primary cause. Historically, many non-Muslim minority religions in West Asia and the Middle East, including Jews, Parsees, Buddhists, Christians, and Druze, also share similar endogamous marriage customs.

A more likely explanation for high consanguinity in these regions is the challenging geography, often consisting of deserts, rugged mountains, or areas with limited resources. In such poorer, rural communities, inbreeding serves a practical purpose: it allows families to consolidate and retain property, wealth, and dowries within the lineage, preventing their loss to other families. This economic advantage, especially pronounced among the poorest and most rural families, often overrides the higher health risks associated with closer genetic relatedness.