Marrying blood relatives is uncommon in many Western countries like the United States and France, where less than 0.1% to 2.6% of marriages involve cousins. This trend extends to Latin American countries, where rates are also low, around 3%.

In contrast, in Africa and the Middle East, marrying cousins is widespread, with some countries exceeding a 50% rate of such unions. This highlights a significant cultural contrast with Western practices.