Which is why humans are very sensitive to interbreeding
https://upload.wikimedia.org/wikipedia/commons/7/7b/Global_p...
https://en.wikipedia.org/wiki/Cousin_marriage_in_the_Middle_...
However, that's racist-adjacent so I doubt there's any actual research or scientific basis for it. They certainly have much higher rates of genetic diseases. As noted in that Wikipedia article: "While babies of Pakistani heritage accounted for roughly 3.4% of all births in the UK (2005), "they had 30% of all British children with recessive disorders and a higher rate of infant mortality," according to research done by the BBC.[46]"