What makes Jesus Christ God is the fact that He was conceived in the womb of the virgin
There is no need to be lurid or foolish about this, I sincerely hope nobody will be. But the God seed was placed in Mary as surely as though God had not by passed the natural process.
Whenever He is addressed in the bible "Son of God, the only begotten" Jesus Christ is being referred to as God.
To me it has always been one of the simplest truths of the bible to understand, that whatever the Father is, the Son must be also. The same in essence, in nature, and in attributes.
And that is how He is presented in the bible.
But Jesus said "flesh and blood does not reveal this but His Father in heaven" this is the dividing line between who is truly in Christ's church and who is not.
I see that before he was conceived, Jesus was declared the divine logos before time began, in the introductory verses in John's Gospel.
I believe that asserting that Jesus was born of a virgin speaks to the importance of Jesus, not to the biology of Mary.
After all, Caesar Augustus was born of a virgin as well. And declared God, son of God and even Savior of the World. All great men in ancient history had miraculous beginnings.
To be blunt however, Jesus himself never refers to himself as divine or as the Messiah. Try as they might, none of the people is able to pin him down.
[I am bracketing the Gospel of John here, because that account is filled with theology and very little history. It is a mystical, Gnostic-tinged Jesus who seems 180 degrees away from the Galilean rabbi of Mark, Luke and Matthew.]