[metmom]

Whatever God did to cause Mary to allegedly be born sinless to sinful parents, He could have done for Jesus to be born of a sinful mother.

If Jesus had to be born of a sinless mother to remain sinless when He is God Himself, then in order for Mary, a mere human to be born sinless, her parents would have had to be sinless as well, and back and back....

[Cronos]

we've repeated it quite often in this thread. Jesus's divinity is not dependent on Mary's being sinless. Quite the contrary, the reason for this sinlessness is:

1. in God's presence, sin cannot stay, it is destroyed.
2. Jesus in the womb was still Jesus Christ, Lord and God.
3. To protect the bearer of God, she had to be made filled with grace and she had to be made free of sin -- for her to be able to bear the Lord

now her own parents being sinful did not affect this as mary is just a creature, and sinlessness being in contact with sinfulness does not affect sinlessness (e.g. a newborn baby in contact with a sinful mother), but the blazing power of God that destroys anything that is tainted with sin, if that is kept in a box/womb which has even a slight tain of sin, that box/womb will be destroyed.