This is not exclusively a muslim issue.
https://en.wikipedia.org/wiki/List_of_coupled_cousins
The risks are dependent primarily upon autosomal recessive genes within the family line. In first cousins they will have 12.5% of genes in common. The increased incidence of birth defects is 2 to 3 percent greater than the general population.
http://www.genetics.edu.au/Publications-...sanguinity
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3419292/
https://en.wikipedia.org/wiki/List_of_coupled_cousins
The risks are dependent primarily upon autosomal recessive genes within the family line. In first cousins they will have 12.5% of genes in common. The increased incidence of birth defects is 2 to 3 percent greater than the general population.
http://www.genetics.edu.au/Publications-...sanguinity
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3419292/
Being told you're delusional does not necessarily mean you're mental.