1st there was only Adam and Eve and they had 2 sons Cain and Abel.
How did mankind flourish after that ? I have no idea how 2 brothers can procreate ?"
Obviously they had more than just Cain and Abel, and yes, there would have been some sibling lovin' goin on at some stage. This came up in another thread recently, the rules against incest didn't come into play until around Moses time, prior to that the gene pool was VERY robust, not like we have now so the concept of inbreeding would have been moot.
