While Christmas reveals the Incarnation to the rest of us, it had already happened back then. Mary was the first to know; and her cousin Elizabeth's unborn baby John (the Baptist) was the first to bear witness. His leaping in the womb was the first act of Christian testimony, a fetal response to a gospel first preached by an embryonic Jesus (perhaps two or three weeks old). As we read this narrative of theology from the womb, our minds turn to a near contemporary who would in due time electrify the ancient pagan world and lay the foundations of its collapse: Saul of Tarsus, also set apart from his mother's womb (Galatians 1:15). Three unborn children in whose hands lay the destiny of humankind. And one of them was not merely the tiniest of humans, he was the cosmic creator, the Word by whom the Godhead has spoken into existence the vastness of time and space. And the One who will one day be our Judge.
Cameron looks back at the meaning of the conception of Jesus in Mary by the Holy Spirit, and to the concrete reality of what happened during Mary's pregnancy:
God took human form; and he took it not simply as a baby, but as the tiniest of all human beings, a mere biological speck, so small and so undeveloped that it could be mistaken for a laboratory artifact, a research specimen, an object for human experimentation. But this speck was God; this complete genetic human organism, in its primitive and undeveloped form, was so much "one of us" as to bear the existence of the Creator. He dignified humanity by taking the form of this creature he had made in his image; and he did it at the most inauspicious and feeble point in the human life story. At the heart of the Christmas celebration lies the fact of all facts, that God became a zygote.
Controversial in our day, yet inescapable as an implication of the incarnation, is the impact the conception of Christ has for current embryonic research:
Therefore: It is important to realize that there are several powerful arguments against using human embryos for research, some of which do not depend on the idea that the embryo is "one of us." And we can argue that the embryo is "one of us"--that human dignity is as indivisible as biological human nature--without ever arguing from theology and Christian belief. But if we are Christians, we have theological underpinnings for such arguments. We believe that all human beings are made in the image of God. We believe that Jesus Christ was God taking human form for himself. And we believe that we started right at the beginning--that incarnation took place in embryo.
The birth of the Bethlehem baby gives cause for celebration around the world. However, the miracle of incarnation took place in time nine months before that holy Advent we recognize by Christmas. Immanuel came to this world, not as a nearly helpless baby but as a totally vulnerable embryo.