Cousin Marriage ... Islam Allows it but.....

Re: Cousin Marriage … Islam Allows it but…

i agree that our today’s religious leadership (if we can call it leadership) is completely devoid of both intellectual and moral fabric …so no expectations from them but my fundamental question is that if science is correct about serious health issues emerging from cousin marriage, then why did islam allow it at first place? why did our religion open a door which would cause so many health issues in coming generations?

we don’t eat pork or drink alcohol because our religion banned them based on health issues but then why didn’t islam ban the cousin marriage?