Mary was an ovulating Jewish teenager. Inside her body was a special egg. This ovum was chosen of the Father to live out the humility of God.  By the Holy Spirit, the seed of God enters the ovum.  Once this union takes place, before the first division of the cell, “It” is not half-human nor half-divine.  “It” is the first cell of the God-Man.  The first step of incarnation!  Going backwards, God not only reduced himself to a man, a teenager, a boy, a baby, but to an embryo, even to a one-cell fertilized ovum inside Mary’s body!  What humility!  What mystery!

And the angel answered her, “The Holy Spirit will come upon you, and the power of the Most High will overshadow you; therefore the child to be born will be called holy—the Son of God.” Luke 1:35 (ESV)