As per the story, Adam & Eve were the first two human species.
Children of Adam & Eve would have been brothers and sisters and whether the story is true or not, we may be here only if copulation had happened between some brother & sister or father & daughter or mother & son. For a modern (so-called) cultured human being it may sound odd but that’s the way human life may have survived for ages
In such a case more than 25% of the population will be having Autosomal recessive syndrome. That’s what you get when you marry in consanguinity (Blood relations)
Now one can realize why some people are REALLY different 🙂
Chasing The Changeless 