Well, I can see where the Catholic’s reaction to the Nestorians came from.
http://en.wikipedia.org/wiki/Nestorianism
“Nestorius’ teachings brought him into conflict with some other prominent church leaders, most notably Cyril of Alexandria, who criticized especially his rejection of the title Theotokos (’Mother of God”) for the Virgin Mary. Nestorius and his teachings were eventually condemned as heresy at the First Council of Ephesus in 431 and the Council of Chalcedon in 451, leading to the Nestorian Schism in which churches supporting Nestorius broke with the rest of the Christian Church.”
They dared to touch Mary.
And we all know and have seen the reactions of Catholics when someone dares to do that.
The question is about the union of the human and divine natures in Christ. If there is indeed a union, without confusion or change, of two natures in one person, Jesus, AND IF that union was true of Jesus from the moment of his conception, then Mary bore God, because the divine nature only exists in 'beings' that are God.
If, however the union is not as described above, then Mary could be thought of as giving birth to the human Jesus who later was united with God in some way not fully described. In THAT case, an argument could be made for NOT saying Mary bore God.
The title Theotokos/Deigenetrix (bearer of God) is a title of Mary, but it is ABOUT Jesus. And the discord was about HOW Jesus could rightly be thought of as having a human and a divine nature.
INTERESTING.
THX.