"Mother of God"

Someone writes: THERE'S NO SUCH THING AS A "MOTHER OF GOD."

My response: Jesus is God Incarnate and Mary gave birth to Him, thus Mary is the "Mother of God". It's really that simple. Jesus was God Incarnate in Mary's womb, he didn't become God after birth. Mary gave birth to the Divine Christ, God Incarnate and she is the "Mother of God". To deny this, is to deny the divinity of Christ. I am not sure why "Mother of God" seems to disturb so many non-Catholics when I dare say, most if not all denominations believe that Christ was born God Incarnate. If you believe that, then what's the problem with "Mother of God"? This is basic Christian theology.