Mary is the mother of Jesus Christ.
Thus, Mary is the mother of God, the Second Person of the Trinity.
And there is a great example of the theological error that claiming Mary is the mother of God can lead to.
Mary is NOT the mother of the divinity of Christ, as saying that she's the mother of the second person of the Trinity states.
Claiming that the second person of the Trinity has a mother, makes him a created being, with beginning, robbing Him of His deity.
Sheesh... the next thing you'll hear will be some bunk that Mary is a conduit of grace for salvation and an intercessor for mankind...
Oh, wait....
Hoss
No it doesn't(covered in Catechism class on the Tuesday that you apparently either missed or slept through..).