Why does the world still embrace the practice of cousin marriage?
While some jurisdictions criminalize the practice, over 10% of global marriages are between first or second cousins. From preserving family wealth to maintaining social honor, the motivations behind these unions are deeply embedded in complex kinship systems and historical traditions across the Middle East, Africa, and Asia.
The motivations for cousin marriage vary significantly by culture. In many Middle Eastern societies, the practice is linked to 'agnatic solidarity'—a preference for maintaining the father's lineage. Anthropologist Ladislav Holý suggests this helps preserve 'symbolic capital' and family honor, as marrying within the kin group allows families to better monitor the conduct of female relatives. In other regions, the practice serves pragmatic ends, such as keeping property within the family, maintaining geographic proximity, or reducing the bride price.
The social perception of these unions ranges from ideal to taboo. In parts of the Indian Subcontinent and the Middle East, cousin marriage remains strongly favored. Conversely, among the Igbo of Nigeria, marrying kin is considered incestuous and cursed. In China, historical patterns show a preference for marrying a mother's brother's daughter (MBD), whereas marrying a father's brother's daughter (FBD) was often viewed as nearly incestuous because the shared surname made the union resemble sibling marriage.
Legal landscapes are equally divided. In the United States, 30 states permit such unions, while 8 states have criminalized them. China enacted a legal ban on first-cousin marriage in 1981 due to health concerns, following a history of varying legality from the Ming to the Qing dynasties. From a biological perspective, the risk of autosomal recessive genetic disorders in children of first-cousin marriages is estimated at 4–6%, compared to 3% for unrelated parents.
The decline of cousin marriage in the West is often attributed to historical religious pressures. For centuries, both Roman civil law and the Catholic Church prohibited marriages within four degrees of consanguinity. Anthropologist Joseph Henrich notes that this relentless pressure may have caused Western European kinship networks to decline, eventually being replaced by voluntary associations like guilds and universities.
Source: Cousin marriage
