I realize this is old, but thought I would respond with some scriptures that might help to answer how it was that Jesus was sinless from the time of His conception to the end.
It was because, according to scripture that I have found about this subject so far, sin cannot be passed down from the female to their offspring at all. Even though certainly all are indeed sinners of course.
And am saying that because of what is written in
Ex. 20:5; 34:7, and Numb. 14:18.
So Jesus was not born as all of us are, that are born after the first Adam.
At least according to those scriptures anyway.
Pretty amazing huh, what God did do.