Why do I mention this obvious fact? Because, according to the bible, the sins of any one of them might be affecting me, personally, at this very moment in time. If we were brought up as Christians and we took the time to listen to what we were taught, or we became atheists and took even more time to learn about the 'secret' inconsistencies in the bible, then we know that the sins of the father will be visited upon the children until the third or fourth generation.
Yet he does not leave the guilty unpunished; he punishes the children and their children for the sin of the parents to the third and fourth generation. Exodus 34:7.
That distinction in itself shows how precise the definition is. The fourth generation will have many more people in it than the third, and yet omniscient gods are apparently unable to tell us whether or not they will have been affected by the actions of their forebears. As usual, the infallible bible does not fail to be completely unclear about the intentions of the god who inspired it.
I'm fairly sure that I know the names of all my great grandfathers, having done a study of my own family history in some detail a few years ago. I have no idea how well they behaved, but given that there were 16 of them, I can't help but worry that one of them did something so terrible that the consequences affect me.
I seem to remember that a kindly gentleman named Zachariah Blanchard Beaver's birth certificate did not reveal the name of his father. (There is probably a clue in his middle name.) It is just as well that his missing father was five generations back! God's disapproval of the consequences of his conception therefore ought not to be the reason why I had such a bloody awful week!
Aside from that - in what way can I be blamed for the sins of my father, let alone his great grandfather?
God might move in mysterious ways, but this isn't mystery. Its just insane and if it were true, typically unfair behaviour.