An inquirer from my Bible Study Program sent me a very interesting question:
For humans, our DNA comes half from our fathers and half from our mothers. I am getting confused here. My question is where is Jesus’ DNA comes from? Did it come from The Holy Spirit? Did Virgin Mary’s DNA form part of Jesus’?
The mystery of the Incarnation (i.e. Word became flesh) means that it is "in [Mary] that the Incarnation of the Word, the hypostatic union of the Son of God with human nature, is accomplished and fulfilled" (JPII, Redemptoris Mater 9). Therefore, Mary is not only "full of grace" (kecharitomene)(Lk 1:28); "because of this gift of sublime grace she far surpasses all other creatures both in heaven and on earth" (Vatican II:Lumen Gentium 53).
There were many different ways that God could have used to save us. In His infinite wisdom, God had chosen to send His Son to save us through the Pascal Mystery, i.e. through his suffering, death, and resurrection. The "critical path", if I may use this popular business term, for accomplishing God's economy of salvation was for the Word to become flesh and dwell among us (John 1:14). Mary was given the singular and sublime grace of being the "woman" from whom Christ took on his body and his human nature.
St. Paul highlighted the significance of the role that Mary played in giving Jesus a body when he said, "When the time had fully come, God sent forth his Son, born of woman, born under the law, to redeem those who were under the law, so that we might receive adoption as sons...crying, 'Abba! Father!'" (Gal. 4:4-6). "Born of woman" is significant in that it underscores the Incarnation - Christ taking on a human body and the human nature from Mary for the redemption of men and humanity. It was a true human body – “born of woman” as St. Paul said – for Jesus is true God and true man (CCC 464).
Having established the singular and significant role that Mary played in the economy of salvation - giving birth to Christ, giving him a true human body; now the answer to the inquirer's question - where did Jesus' DNA come from? - has become self-evident.
From the above scriptural analysis, it's clear that Jesus' body came from Mary - God made a point of seeing that it did: she was "overshadowed" by the power of the Holy Spirit; she conceived; and baby Jesus grew in her sacred womb. She is sublime and surpasses all other creatures on earth and in heaven because of this special vocation - giving birth to Jesus, giving him a human body and the human nature. It follows that Jesus' body had his mother's DNA since it came from her. It was God's will that Jesus had Mary's DNA!
According to the inquirer, biologically a child's DNA must come from a father and a mother. How is it possible that Jesus received his DNA from just Mary alone? The question is similar to Mary's own question to Gabriel: "How can this be, since I have no relations with a man?" (Luke 1:34). As a result, its answer also is similar to the answer that Gabriel gave Mary: "The holy Spirit will come upon you, and the power of the Most High will overshadow you...for nothing will be impossible for God" (Luke 1:35-37).
Does this mean half of Jesus' DNA came from the Holy Spirit? As a divine Person, the Holy Spirit is neither man nor woman. He doesn't have a human body. While it was the power of the Holy Spirit that caused Mary to conceive, it's wrong to say that half of Jesus' DNA came from the Holy Spirit. With humility, we have to admit that we don't know exactly how God did it, but we do know that "nothing will be impossible for God".