(You are in contradiction with the Scriptures, then. When asked by his disciples if a man had been born blind because of the sins of his forebearers, Jesus denied that it was so. He also denied that he was blind for something he had done himself. (John 9:1-3) In turn, Jesus suggested that God had si gled out this man to suffer decades of blindness so that he could perform a heal miracle spectacle to awe people. This explanation also makes god look like a moral monster who plays with people's lives and doesn't really care for their suffering.
This is a very controversial event. It's used to defend Calvinism. This is a very very long discussion.
In any case, a god that makes someone pay for the sins of his forebearers is a moral monster who doesn't deserve to be worshipped.
It's not sinS and not all ancestors.
It's a very specific sin regarding the human nature itself committed only by the first souled human couple in a very specific situation (somewhere in Mesopotamia about 6.000 years ago).
The physical Eden is a recent interpretation. The old traditions said the Eden are in the spiritual realm (the paradise that Jesus told to the good thief and/or the Bosom of Abraham. Islam has the same view).
More than our ancestors they were representing the very human nature. Just like an entire country must face the consequences of the acts from their leaders. Even those who didn't vote (or agree with) in the leaders must face the consequences too.
It's not that hard to understand that.