Proc Natl Acad Sci U S A. 2026 Sep 8;123(36):e2600906123. doi: 10.1073/pnas.2600906123. Epub 2026 Aug 31.
ABSTRACT
Cousin marriage, practiced by over 10% of the world’s population, restructures kinship networks by overlapping blood and affinal ties. Theory makes competing predictions about how such kin density shapes intrahousehold conflict. “Protection” accounts posit that consanguinity aligns spouses’ interests and increases kin oversight, reducing men’s incentives and opportunities to use coercion. “Constraint” accounts, by contrast, emphasize that dense kin networks can prioritize family cohesion over women’s autonomy, potentially suppressing help-seeking and facilitating control. Here, I adjudicate between these hypotheses using data on ~36 to 46,000 women from Egypt, Jordan, Pakistan, and Türkiye. Using cluster-fixed-effects models that compare women within the same Demographic and Health Survey primary sampling units and survey waves, I find that marriage to a first cousin is associated with a 2.5 percentage-point lower probability of physical intimate partner violence relative to nonconsanguineous unions (≈11% lower relative risk). Parallel reductions are observed for coercive controlling behaviors and estimates are robust to matching on observed confounders. The protective association for physical violence is stronger for patrilateral than matrilateral cousins, consistent with protection depending on kin with recognized authority over men in patrilineal systems rather than generic relatedness. In Türkiye, the association persists after adjusting for both spouses’ parental consanguinity, suggesting that it is not explained solely by family-level characteristics associated with the intergenerational practice of cousin marriage. These findings indicate that, in these settings, consanguinity is associated with lower reported violence and control.
PMID:42673449 | DOI:10.1073/pnas.2600906123
