Africa

• Certain nations and tribes in Africa accept cousin marriages more readily than others. For example, in Ethiopia, the majority of the population is against cousin marriages. Nigerians, however, preferentially practice cousin marriage. According to Australian geneticist A.H. Bittles, 35 percent to 50 percent of all sub-Saharan African populations either accept or practice cousin marriages.
  
  

Middle East

• Cousin marriage in the Middle East is traceable throughout all recorded history. A study conducted in 2009 by the Reproductive Health Journal found that first cousin marriages account for 25 percent to 30 percent of all marriages in the Middle East. Included in this are both Middle Eastern Muslims and Jews.
  
  

South Asia

• South Asia includes Pakistan, India, Sri Lanka and Bangladesh. Regionally cultures within South Asia differ as to the prevalence of cousin marriage. South Indians are more likely to marry cousins than people in north and central India. Cousin marriages in Pakistan and Bangladesh are prevalent. Cousin marriages in Sri Lanka are less prevalent than in both India and Pakistan.
  
  

Japan

• Cousin marriage in Japan is acceptable, although it has declined in recent years. Japan's Prime Minister Naoto Kan is married to his cousin. Cousin marriages saw a decline after World War II with an increase in industrialization and Westernization. Although the prevalence has declined, most Japanese citizens do consider the practice taboo.