[crosshairs]

God had no beginning and He has no end. God created Mary. Mary cannot be the mother of God. Mary however is the mother of the human Jesus, in the sense that she was used as a vessel for his birth.

[D-fendr]

If you always keep in mind the Most Holy Trinity, the point is simple.

Mary cannot be the mother of God.

Only if Jesus is not God or Mary is not His mother.

Mary is the mother of Jesus;
Jesus is God;
therefore, Mary is the mother of God.

For "God" substitute: "President of the Student Council" or whatever, and it's the same.

It is a simple, clear, true statement of the Incarnation, fundamental to the Christian faith.