The simplest explanation that doesn't require us to dismiss the Bible is that, like it or not, Cain was a redneck--well, he married his sister. Incest would not have been a problem when man was still so close to physical perfection. Even Abraham, many centuries later, married his half-sister with no unfortunate consequences (unless her barrenness before finally having Isaac is seen as one).
We only read of Cain, Abel and Seth because of the stories that surround them. We only have the Cain and Abel story because of the murder, and we only read of Seth because he was an ancestor of Noah. It is possible that both Cain and Abel had kids before Cain's exile? Were Cain's descendants contemporaries of Seth's? Several had similar names (and some suggest they were really originally from the same list, but two different lineage traditions were created).
Everything else that may have happened in the first few chapters of Genesis (or indeed, anywhere during the times of the Bible) that is not specifically addressed is open to speculation.
This message has been edited by DeclinetoState, 03-18-2006 01:45 PM
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