If the idea of marrying your cousin has sent you into a tailspin, you might be surprised to learn how widespread this practice is today.
Worldwide, more than 10% of marriages are between first or second cousins.
It is widely known that children of first cousin marriages are at increased risk of developing genetic disorders, yet the practice remains strongly favored in places such as the Middle East and South Asia.
Even in the United Kingdom, there is no legal barrier preventing two cousins from marrying.
Some cultures continue to practice cousin marriage on the grounds that it keeps values intact, preserves family wealth, keeps the family geographically close, maintains traditions, and strengthens family ties.
Meanwhile, in jurisdictions including mainland China, Taiwan, North Korea, South Korea, the Philippines, and 24 of the 50 United States, it is legally prohibited.
These are the places where cousin marriage is still legal:
The Middle East
Marriage between cousins has been permitted in the Middle East throughout recorded history.
In central Arabia, men had the right to marry their father’s brother’s daughter.
Women are not technically forced to marry their male cousins, but they cannot marry anyone else without their consent.
Horrific incidents have been recorded in Iraq where men killed their cousins for trying to marry someone else.
Anthropologist Ladislaw Holly once said that the practice was an expression of the Middle Eastern preference for solidarity with paternal lineage, while others have said that it was adopted because it allowed men to control women.
A 2009 study found that Arab countries have some of the highest rates of marriage between closely related people in the world, and that the rate of marriage among first cousins can reach 30 percent.
It’s not a dying trend either, with Qatar, Yemen and the UAE now seeing an increase in consanguineous marriage rates.
An estimated 35 to 50 percent of the entire population of sub-Saharan Africa is said to favor or accept cousin marriage.
Muslims in Nigeria’s largest ethnic group, the Hausas, preferentially practice it and allow husbands to have polygamy.
A 1974 study found that 51% of marriages among the Yoruba people in Nigeria were between relatives, including uncle-niece marriages.
In the United Kingdom, consanguineous marriage is legal and not rare, while in France it is legal but considered taboo and relatively uncommon.
A study of middle-class Londoners in the 1960s revealed that only one in 25,000 marriages was between first cousins.
In Germany, this is legal but rare and controversial, and in Greece, marriage between third cousins is permitted and considered positive.
In some other European countries, such as Spain and Italy, cousin marriage is legal and accepted in certain regions but not in others.
This practice was common in Italian regions such as Calabria and Sicily, where first cousin marriages accounted for nearly 50 percent of all marriages in the 20th century.
The Prime Minister of the Netherlands recently proposed a ban on first-cousin marriage with the aim of preventing “import marriages” from other countries.
As of 2014, 19 US states allow marriage between first cousins, only seven states allow some marriages between first cousins, and 24 states prohibit marriage between first cousins.
Six states have banned first cousin marriage at once.
China’s two special administrative regions, Hong Kong and Macau, do not place any restrictions on marriage between cousins, although it is banned on the mainland.
First cousin marriage is allowed in Japan but is now less common than it used to be.
Marriage between relatives is legal and relatively common in Afghanistan, with 46.2 percent of marriages falling into this category.
It is also legal and common in Pakistan, while attitudes vary greatly by region and culture in India.