The map above shows the estimated share of all marriages in each country that are consanguineous, which usually means between first and second cousins.
The data used comes from World Population Review:
| Country | Consanguineous (Cousin) Marriages |
|---|---|
| Pakistan | 61.20% |
| Kuwait | 54.30% |
| Qatar | 54% |
| United Arab Emirates | 50.50% |
| Sudan | 50% |
| South Sudan | 50% |
| Afghanistan | 49% |
| Mauritania | 47.20% |
| Iraq | 46.40% |
| Yemen | 44.70% |
| Iran | 39.50% |
| Saudi Arabia | 38.90% |
| Libya | 37.60% |
| Oman | 35.90% |
| Syria | 35% |
| Bahrain | 31.80% |
| Palestine | 31.60% |
| Egypt | 29% |
| Jordan | 28% |
| Guinea | 25.90% |
| Lebanon | 25% |
| Sri Lanka | 23% |
| Algeria | 22.60% |
| Turkey | 21.10% |
| Tunisia | 21.10% |
| Nigeria | 19.90% |
| Morocco | 19.90% |
| Bangladesh | 17% |
| Israel | 10.40% |
| India | 7.50% |
| Malaysia | 6% |
| Cambodia | 6% |
| El Salvador | 4.90% |
| Japan | 3.90% |
| Honduras | 3.40% |
| Costa Rica | 3.40% |
| Puerto Rico | 3.30% |
| Colombia | 3% |
| France | 2.60% |
| China | 2% |
| Brazil | 2% |
| Germany | 2% |
| Spain | 2% |
| Ecuador | 2% |
| Uruguay | 2% |
| Canada | 1.50% |
| Portugal | 1.50% |
| Mexico | 1.30% |
| Venezuela | 1.30% |
| Chile | 1.30% |
| United Kingdom | 1.10% |
| Italy | 1.10% |
| Belgium | 1% |
| Norway | 0.70% |
| Hungary | 0.50% |
| Argentina | 0.40% |
| Australia | 0.20% |
| Bolivia | 0.20% |
| United States | 0.10% |
| Russia | 0.10% |
| Philippines | 0.10% |
| Ukraine | 0.10% |
| Peru | 0.10% |
| Netherlands | 0.10% |
| Cuba | 0.10% |
| Sweden | 0.10% |
| Czech Republic | 0.10% |
| Belarus | 0.10% |
| Slovakia | 0.10% |
| Ireland | 0.10% |
| Panama | 0.10% |
| Croatia | 0.10% |
| Belize | 0.10% |
Consanguineous marriages, marriages between people who are biologically related as second cousins or closer, are a deeply studied and complex social phenomenon, with important biological, cultural, and social dimensions.
Here’s a more detailed overview:
What “Consanguineous Marriage” Means
A consanguineous marriage is typically defined as one between individuals who share a common ancestor within the past few generations, most commonly first cousins, but sometimes also second cousins or even uncle-niece relationships in certain societies.
Such marriages are common in parts of the Middle East, North Africa, South Asia, and among certain diaspora and religious groups.
Globally, it’s estimated that 10-20% of marriages are consanguineous.
Genetic and Health Risks
Increased risk of genetic disorders
- Every person carries several recessive genetic mutations that are harmless unless inherited in two copies (one from each parent).
- In consanguineous unions, both partners are more likely to carry the same recessive gene variants because they share ancestry.
- The risk of autosomal recessive disorders (e.g., cystic fibrosis, certain metabolic disorders, hearing loss, congenital anomalies) therefore rises.
Typical risk estimates:
- In the general population: 2–3% risk of birth defects.
- In first-cousin marriages: ~4–6% risk, roughly double the background risk.
Higher rates of infant mortality and morbidity
- Studies show a modest but statistically significant increase in infant mortality and childhood morbidity in populations with high rates of cousin marriage.
Possible fertility issues
- Some research links consanguinity to reduced fertility, increased miscarriages, or lower overall genetic diversity in small communities, though this is not universal.
Why Consanguineous Marriages Occur
Despite the risks, these marriages are often socially and culturally valued. Common reasons include:
Social cohesion and family unity
- Marrying within the family strengthens kinship bonds, reinforces trust, and maintains property or inheritance within the extended family.
- It can provide a known and trusted partner and preserve family honor or cohesion.
Economic and practical reasons
- Keeps wealth and land consolidated.
- Reduces dowry costs or ensures that a woman marries someone her family knows well.
Cultural and religious traditions
- In some societies, cousin marriage is an established custom endorsed by tradition or interpreted as permissible in religious law (e.g., in Islamic jurisprudence, cousin marriage is allowed).
Limited marriage pools
- In small, isolated, or endogamous communities, the gene pool and marriage options are restricted, so consanguineous marriages are more likely.
Changing Patterns and Public Health Approaches
- Education and awareness: Health professionals often counsel families about the genetic risks associated with close-kin marriage.
- Genetic counseling and screening: In countries like Saudi Arabia, Iran, and Pakistan, premarital genetic testing programs have been introduced to reduce recessive disease incidence.
- Urbanization and globalization: Younger generations in many regions are increasingly marrying outside extended family networks.
What do you think about it?
Bob Worsley says
It would be interesting to see how far away you live from your parents. In my case UK vs Australia.
Hyungnam Gu says
In mainland China, first-cousin marriage is prohibited under the Civil Code (previously the 1980/2001 Marriage Law), citing eugenic reasons to avoid genetic risks. The ban focuses on collateral relatives within three generations. While common in the past, such unions are now legally void, although they were historically prevalent in rural areas.