Well let me make another assertion:
Is it possible that Cain was conceived through the advesary? I point to the gospel of philip:
"He who has been created is beautiful, but you would <not> find his sons noble creations. If he were not created, but begotten, you would find that his seed was noble. But now he was created (and) he begot. What nobility is this? First, adultery came into being, afterward murder. And he was begotten in adultery, for he was the child of the Serpent. So he became a murderer, just like his father, and he killed his brother. Indeed, every act of sexual intercourse which has occurred between those unlike one another is adultery."
and then adam had sex with eve? and Able was born? but because Able was murdered...thats why we were from adam's image? through seth? Which explains why he isn't mentioned in the lineage? It would also explain why there's an enmity between the two different types of 'seeds' ...? I mean it IS possible for a women to conceive TWO offsprings from two different men. I mean it doesn't say 'adam knew his wife AGAIN ' and then she bore able. It's almost as if they were twins...but from different fathers. i'm just throwing this out htere to see what happens
Mr. Me