Where did that sin come from if it wasn't a result of the 'Fall in Eden'? If Jesus death on the cross is a sacrifice of atonement exactly what is he atoning for?
It came from us, and he is atoning for us... all of us.
You could take Genesis literally, and believe that sin entered the world when the first sin occurred by them, because we learned it from them. Of course, then we'd have to assume that we would have done better than Adam and Eve... and none of us knows the answer to that. You could ALSO take the story symbolically, as in Adam and Eve simply represent what we all have done and continue to do. There are other ways that people take that story as well.
But the simple fact is that we do all sin. Christ's sacrifice and atonement was for us and our sins. Even Paul said his atonement did not follow just one sin; it followed many sins. Ours. No reason to think Adam's wasn't in there too, but it wasn't just for him and his sin. I think the people who look at the 'ransom' sacrifice in the way that the JW's do, might still be doing what Adam and Eve did... which is look for someone else to blame for what they do themselves:
"The world is screwed up because of Adam and Eve, not because of us. If they hadn't sinned... etc, etc."
Tammy