Assuming for the most accepted hypothesis regarding the chronological order of the canonical Gospels, i.e., Mark, Matthew/Luke, and John, and that the later evangelists were to a certain degree dependent on Mark’s Gospel, it is perhaps interesting to note that:
1. Mark as the earliest Gospel does not include the birth narrative of Jesus. The genesis of Jesus of Nazareth is the ministry of John the Baptist. John proclaimed the advent of the one who was to come; Jesus proclaimed the advent of the kingdom.
2. Then Matthew/Luke included the birth narrative(s) when they wrote their respective Gospels. Matthew added a genealogy tracing back to Abraham, an angelic appearance to Joseph, a birth narrative with the magi, and an exodus to and back from Egypt.
3. Luke, on the other hand, added the birth narrative of John the Baptist himself, a different version of genealogy tracing back to Adam, an angelic appearance to Mary, and a birth narrative with the shepherds and Simeon/Hana (he added an account of Jesus’ childhood as well, which is a unique feature found only in Luke).
4. Despite these differences, there are at least three recurring features of these birth narratives in Matthew and Luke: (1) Jesus was conceived from the Holy Spirit, (2) his parents were Joseph and Mary, and (3) he was born in Bethlehem.
5. John, finally, extended the genesis of Jesus even much further back to the beginning of the created universe itself: “In the beginning was the Word.”
6. Only after adding these narratives, Matthew/Luke/John then, somewhat consistently, proceeded with the ministry of John the Baptist, which was the original starting point in Mark.
7. For those who have ears to hear, these birth narratives are superbly constructed, heavily reliant on the Hebrew Scriptures, and theologically rich.