The answer is: God

Mark 1:1 - Throughout the gospels Jesus is called the Son of God and had no genetic connection to Joseph. Jesus was born from God's power, the Holy Spirit, acting upon Mary and for this reason his father was God and his mother was Mary. He was therefore called both the Son of God and also the Son of Man.

The conception of Jesus is one of the most profound mysteries in the Christian tradition. In Mark 1:1, right off the bat, we’re told about His divine identity as the "Son of God," setting the tone for who Jesus is from the very start. It's intriguing to explore how this phrase echoed throughout scripture long before His birth. The idea of a son representing God isn't new; one can think of Israel itself being referred to as God's firstborn son in Exodus 4:22, which hints at a deeper relational context extending beyond just biological connections.

The Holy Spirit's role in Jesus' conception emphasizes divine initiative; it wasn’t through usual human means. This idea prepares us for the extraordinary work Jesus would go on to do, impacting humanity in ways no earthly father could entirely stimulate. Despite being conceived by divine means, Jesus still embraced human experiences—joys, sorrows, struggles—the very essence of being the "Son of Man."

There's fascinating trivia in that early traditions linked Jesus with messianic figures from the Hebrew scriptures, such as David. Both kings had unique calls from God and were seen as important in bridging the Old and New Testaments. Thus, the narrative of His birth invites all of us to reflect on deeper questions of identity and purpose, demonstrating the exceptional intertwining of the human and divine even from the very beginning of His story. Isn’t it marvelous how these ancient texts bridge between law, prophecy, and fulfillment all knitted together through one individual?