A just so story hardly explains original sin. Genesis is historical narrative.
Neither does a literal reading of Genesis. The story shows that we are fundamentally not capable of being sinless. Even when put in a perfect environment, we sinned the first time we were tempted. The story doesn't say where this weakness came from. It just illustrates it.
Fortunately Paul's understanding of Christ doesn't depends upon this. he's making an analogy. As sin entered through one man, so did salvation. It was a great comparison, but nothing in his theology of Christ depends upon it. I don't think it's clear whether Paul was simply wrong about Adam or he was using a well-known story for comparison. I suspect he was wrong, but I don't insist on it.
Upvote
0