[gbcdoj]

The Christian truth is that the Son of God became incarnate and assumed the form (or rather, nature) of a man. Phil. 2:6-11.

Therefore, in bearing Jesus Christ, the Son of God and Son of Man, the Blessed Virgin truly became the Mother of God, according to the humanity which he assumed. Otherwise one denies the reality of the incarnation: that the Word became flesh and dwelt among us.

[whispering out loud]

I don't have to accept the title mother of God to accept the reality of the incarnation. Mary was no doubt the vessel that God chose to usher his human form into the world, that doesn't make her his mother. The term mother indicates that she was paramount to the conception of God. "Before there was time, I am" God himself was not conceived, the flesh he assumed on earth was conceived, but the flesh was not who he was, it was merely a vessel he indwelt to work his plan.