ok, i went to a presentation recently where jean-laurent casanova reported data which suggest that most deaths due to infectious diseases are necessarily due to genetic predisposition, and not necessarily due to infection as such. casanova presents data which show that almost all humans are infected with a host of pathogens which only kill a small minority, generally children and the old. infection is sufficient & necessary for manifestation of disease, but casanova suggests that a particular genetic profile is necessary, and some profiles predispose one to death.
what relevance does this have to islam? re: the contention that cousin marriage does not cause abnormality, i pointed out the prevalence of recessive diseases among this group. casanova shows that out of a tiny minority of children that die from certain rare infectious diseases in the western world, 10% are the offspring of cousins. this strongly implies recessive alleles which only are unmasked when close relatives produce progeny, but it also points to likely higher overall rates of infection for the children of cousins even if the don’t die. a higher rate of flu & other respiratory ailments for children, etc., in one’s lifetime isn’t, in my opinion, a strong reason for why cousins should not marry IMO, but, it does suggest that those who make the claim that cousin marriage (at least first cousin marriage) is totally without cost aren’t correct.
