Part of the difficulty is that we live in an age where most folks reject anything that is not material - whether they realize it or not.
Thus, someone says that being one’s mother means that one could not have existed prior to one’s conception. As if the mother and the father are the entire progenitors of the child. But that's not true.
We all have souls. Our parents did not bring our souls into existence. God did. Our parents only gave us our physical body, not our souls.
Yet, just because my mother didn't give me my soul, but only my human body, I don't refuse to call her my mother. We don't say, either, that she is the mother of my body but not of my soul, because mothers are mothers of entire persons, not of pieces thereof. My mother is mother of all of me, body and soul, even if she didn't produce all of me.
Similarly it is with Mary. It's absolutely true that she had nothing to do with “creating” the Divine Nature of Jesus. Yet, she is the mother of the entire person, Jesus Christ, and He is God. Thus, she is the Mother of God.
But the subtle materialism of the age obscures this truth, and makes people fall back into the ancient heresy of Nestorianism.
sitetest
This thread is just dripping with Nestorian heresy (among others).
Bingo.