I was raised a bad/good Protestant and taught to hate/fear Catholicism and all things Roman. Indeed, the idea of ‘mother of God’ was such a pagan influence, that all Catholics were merely nice dressed Zeus worshipers; however, ‘mother of God’ is not nearly as heinous as I – and I assume, others – have been taught.
One day in the early fifth century, a priest preached a stirring sermon in the presence of the patriarch of Constantinople. His subject was the holy mother of Jesus. The preacher continually referred to Mary as the “Theotokos” meaning “God-bearer” or mother of God. This was no innovation — Christians had invoked Mary under this title for at least two hundred years. Nevertheless, at the close of the sermon, the patriarch ascended the steps of the pulpit to correct the preacher. We should call Mary the Mother of Christ, said Patriarch Nestorius, not the Mother of God. She was the mother of his human nature, not the mother of his divinity.
The controversy is between Θεοτόκος and Christotokos. First, we should note that the proper translation is not necessarily ‘Mother of God’. Mother in Greek is μητέρα. Theotokos is literally ‘God-bearer’ or ‘who one gives birth to God.’ Not the exact same thing as ‘mother of God.’ (I would prefer, if I had to use, ‘God-bearer’.)
One of the first notion of this title used for Mary is found in Alexander, Bishop of Alexander, to Alexander, Bishop of Constantiople.
After this we know of the resurrection of the dead, the first-fruits of which was our Lord Jesus Christ, who in very deed, and not in appearance merely, carried a body, of Mary Mother of God, who in the end of the world came to the human race to put away sin, was crucified and died, and yet did He not thus perceive any detriment to His divinity, being raised from the dead, taken up into heaven, seated at the right hand of majesty.
Why was it necessary to use it then? (Origen supposedly used it, but a much later author attributed it to him based on a text which may not be genuine.) Because, Arius was standing against those who believed that Christ was fully God – not a god, or a second God, or even another God. Further, this secured against the idea that Christ was born a mere man and then adopted into the Godhead, which a variety that heresy worked in and out of the Church. Alexander was using it to secure in the minds of his readers not a (more) special position for Mary but to secure the orthodox position that Mary had gave birth to God in the flesh. He was God before the flesh and God after the flesh, but He never the less was God.
It was only later that it became a major point of adoration for Mary.
I believe that it would be okay to call Mary Θεοτόκος as we declare to the world in that instance that she gave birth not to a mere man, but to God.
Check out Brian LePort‘s post as well.