So now you presume to know the mechanisms of God and what he MUST do? Mary's role was special and unique in all of history. Get over it.
No sir I don’t presume at all. It is the Roman position of presumption. There is no evidence Mary was conceived without sin. I was taking your presumption to a logical geometric progression. If Mary was conceived without sin then her father’s seed given by way of Adam would need to be without sin. The only other possible outcome is that Mary was not conceived in the manner all other humans are conceived. Which leads one to suggest she as well was conceived from On High. But I don’t even think a Roman Catholic would suggest such heresy.