Mack, you have provided a sort of answer, but the rest of the crew has not.
I am treating them differently than you.
They want to hold absolutely that "all have sinned." Not "all have sin" or "all have a sin nature."
No.
They want to make absolute "all have sinned" so it is entirely reasonable to ask what this sin is that a newborn has committed.
SD
Yes.
A baby lacks the ability to discern right from wrong. Thus it can not be said to be exercising a free will choice to do what is "wrong." It can not sin.
SD