Proof: Cousin Marriage is also Incest

For centuries, in Muslim families, marriages between first cousins have been taking place generation after generation. That is, in every generation, some first cousins end up marrying each other. According to science, with such continuous cousin marriages in each generation, the proportion of shared genes keeps increasing.

Science is clear that:

• First cousins share, on average, 12.5% of their genes. This is the same proportion as between a grandparent and grandchild. Calling a cousin marriage a “normal marriage” is, in reality, self-deception. From a scientific perspective, such a relationship is as incestuous as a grandfather with his granddaughter or a grandmother with her grandson.

The real danger increases over time. If cousins continue to marry within the family across generations:

• By the fourth generation, cousins share 25% of their genes, the same as half-siblings. Marriages at this stage are equivalent to unions between step-siblings, and the risk of genetic diseases and disabilities in their children multiplies significantly.

• By the eighth generation, cousins can share 50% of their genes, the same proportion found between full siblings or between parents and children. Such marriages are, in effect, the genetic equivalent of direct incest, with children facing severe health risks.

Double Cousins Marriage: The Greatest Risk

In Islam, marriage between “double first cousins” is also considered permissible. This occurs when two brothers marry two sisters. Their children (i.e. the double cousins) already share 25% of their genes from the very first generation, scientifically equivalent to half-siblings.

If this pattern continues:

• By the second generation, the risks to children multiply.

• By the third generation, the shared genes reach 50%, the same as between parents and children or full siblings.

In other words, third-generation double cousin marriages are scientifically equivalent to incest between a mother and son or a real brother and sister. Children born from such unions face extremely high risks of birth defects and incurable diseases.

Science shows that children born from such unions are at a much higher risk of:

• Congenital heart defects

• Mental retardation and intellectual disabilities

• Genetic disorders such as thalassemia

• Impaired vision and hearing

• Even premature death

Research from the UK, Pakistan, and the Middle East confirms that mortality and disability rates among children in cousin-marriage families are far higher than in the general population.

Based on two reports by BBC (Report1 & Report 2):

• It is estimated that at least 55% of British Pakistanis marry their cousins, and this practice persists into the second generation.
• According to statistics, British Pakistanis are 13 times more likely to have children with genetic disorders than the general population of Britain.
• In Birmingham city, 10% of children born to first cousins either die in infancy or develop severe disabilities due to recessive genetic disorders.
• Although the Pakistani community comprises only 3% of all births in Britain, they account for 33% of all British children with such disabilities. This means that if 55% of British Pakistanis have cousin marriages, then the 1.5% population of Britons who engage in first cousin marriages accounts for 33% of all British children with genetic disorders. [Source:  Paper by Darr and Modell published in 2002 - Genetic Counselling and customary consanguineous marriage. Nature Reviews: Genetics, Vol 3 March 2002]

This is not merely a matter of “religious permission”; it is about the health and survival of human lives and generations and the pain that it causes to innocent disabled children. No matter what name it is given, incest always leads to the same outcomes: diseases, disabilities, and broken lives.

Shared Genes Across Generations

Double First Cousins