According to the World Population Review, first cousin marriages are common in Muslim-majority nations. There are studies showing that first cousin marriages have a significant negative impact on intelligence, and health over generations.
Some Mennonites also marry first cousins.
Studies comparing health and intelligence to first cousin marriages are dated or not considered definitive. However, in general, from the limited studies, inbreeding generally produces negative results in intelligence and health compared with distant unions.
IQ tests are unreliable. At best, they test linear skills and rely on the person’s education and culture.
That being said, the BMJ reported that a study of consanguinity and intelligence reveals a significant correlation between the two. Consanguineous marriages, particularly between first cousins, are common in certain cultures and can lead to high rates of consanguinity. This increased consanguinity is associated with lower IQ scores, as seen in the Ansari Muslims of Bhagalpur, where inbred children showed lower verbal and performance subtest scores and lower full-scale IQs. The study also found that both consanguinity and locality affected IQ, with the interaction between these two factors being significant.
In Pakistan, 30% of first cousin marriages result in children with disabilities.
According to Innovations in Clinical Neuroscience, the implications of consanguinity on cognitive behavior highlight the importance of understanding the genetic and social factors that influence intelligence and the potential need for public health programs to address these issues.
Consanguinity is not a good idea, and we should be aware of it and how it affects society.
Costly to nations who allow these savages in.