"OBVIOUSLY"
When Mary is called the *mother of GOD* that is EXACTLY what is being said and taught.
The only people who believe that the Church teaches this are some Protestants.
Even Wikipedia understands this:
Within the Orthodox and Catholic tradition, Mother of God has not been understood, nor been intended to be understood, as referring to Mary as Mother of God from eternity — that is, as Mother of God the Father — but only with reference to the birth of Jesus, that is, the Incarnation. This limitation in the meaning of Mother of God must be understood by the person employing the term.
The term, Theotokos can be traced as far back as Origen, in 254 A.D.
And really, the term goes all the way back to the New Testament, when Elizabeth refers to Mary as, "the mother of my Lord."
The term is simply a shorthand way of expressing the profound and singular grace of having being chosen to be the Mother of the Man/God, Jesus, with the emphasis being given to Jesus' divine nature. Certainly, her having given birth to a human son would not have been seen as especially significant.