Still bugging me. I'm listening to the Church History podcast of Reformed Theological Seminary, and we've gotten to Nestorius and the Council of Ephesus. It seems that the "proper" interpretation of the events is that Nestorius was a heretic, because he believed in two persons in Christ, which we know because he opposed the term Theotokos (literally 'God-bearer', but translated 'Mother of God') used for Mary.
Let's get this straight: Mary is not Theotokos.
"But then you deny Christ's divinity!"
No. Calling Mary Theotokos makes her divine. I don't care how many Church Fathers used that term and had in the back of their mind the proper understanding of Mary as just a woman and of Jesus as the God-man. The blasphemy is written in the words up front. For Mary to "bear" God, she has to be the source of the material God is made out of, she has to feed God with spiritual food (since God is spirit) while nurturing Him in her spiritual womb or in her spiritual arms. Mother, Father, Sister, Brother, are all relationships of like kinds. They can only be used in that context. To say that "Mary is the Mother of God only means Jesus is simultaneously fully God and fully man," breaks this proper usage of the term. Only God could be the Mother of God.
You have a war of conundra here. One side says that to deny that Mary is the Mother of God logically leads to a denial of the Hypostatic union of divine and human natures in the one person of Christ. My side says that to affirm that Mary is the Mother of God logically (and with fewer logical steps) leads to the blasphemy that Mary is God.
By the way, I completely affirm the hypostatic union of divinity and humanity in the one person of Christ.
Here's what really bugs me. Why is there a 'term' in the first place? Since when did she come on the scene? Why is she that important that we should have epic arguments of her title? Why the pressure? Could it be that Semiramis/Aphrodite/Diana of the Ephesians/Ashtoreth/Artemis is trying to rear her ugly head and usurp the position that properly belongs to God?