Crossan understands the canonical birth narratives to be theological fictions, as Mark, Q, and the Gospel of Thomas, which he views as the earliest historical sources, do not contain any form of birth narrative. Drawing Jesus into parallel with Caesar Augustus, Crossan writes concerning the miraculous birth narratives that, “greatness later on, when everybody was paying attention, is retrojected onto earlier origins, when nobody was interested. A marvelous life and death demands and gets, in retrospect, a marvelous conception and birth.”[1] Crossan understands the birth narrative of the Lucan account as comparing the birth of Jesus to that of John, who Crossan argues to be more historically prominent.[2] Similarly, the Matthean birth and flight narrative seeks to portray Jesus in light of the life and exodus of Moses, reflecting a theological rather than historical origin.[3] Crossan argues that certain canonical gospel narratives, including the birth narrative, are not historically accurate but rather are theological narrative based upon a reading of Old Testament prophecies and events into the life and times of Jesus. Accounts of the virgin birth, the Davidic line, the magi, shepherds, angels, role of King Herod, and flight to Egypt are all derived not from historical events, but instead a specific reading of Old Testament texts[4] and general chronological data about the life of Jesus that would have been known by his earliest disciples.[5] Thus, Crossan places little historical importance on the birth narratives of Jesus, arguing that in all likelihood he was born and raised like every other Galilean Jewish peasant in the first century.
Wright actually pens very little concerning the birth narratives of Jesus in the sources that we are employing for this series.[6] When considering the context of Jesus, Wright tends to compare him not to Octavian but to Jewish leaders and revolutionaries of a similar context and chronology, including Judah the Hammer, Simon the Star (or Simon son-of-the-Star), Herod the Great, and Simon bar-Giora.[7] Comparing him to these revolutionaries casts the historical Jesus as rather meek or even pathetic character, for compared to these leaders his bland historical accomplishments are of far less consequence. Notably Jesus’ relationship with John the Baptist and their apparently shared vision (shared enough for Jesus to be baptized over) are not fully explored by Wright.[8] It may be that where Jesus comes from does not fit Wright’s perspective on the significance of the end of his life, or that there remains too little evidence outside the canonical gospels concerning the narratives presented to warrant a historical critique. Whereas Crossan takes lack of external evidence to mean that the narratives are fiction, Wright seems to understand the same lack of counter-example as demonstrating that the canonical accounts had no oppositional claims in the ancient world from whence they came. Thus, Wright has little to say about the birth of the historical Jesus in our sources, only that proper contextualization within his group of peers remains important.
[1] John Dominic Crossan. Jesus: A Revolutionary Biography. San Francisco: Harper San Francisco, 1994. 6.
[2] Ibid., 5-10.
[3] Ibid., 10-15.
[4] Ibid., 15-28.
[5] For example, that he was likely born around the time of the reign of Herod the Great.
[6] Even in the opening volume of Wright’s Christian Origins and the Question of God series, The New Testament and the People of God (Fortress Press: Minneapolis, 1992) shockingly little directly concerns itself with the birth and early life of Jesus of Nazareth.
[7] Tom Wright. Simply Jesus. New York: Harper Collins, 2011. 104-116.
[8] Though the relationship of Jesus and John is considered with regards to Jesus’ prophetic status (see Jesus and the Victory of God, 160-2).
Pursuing Veritas 
I found some info concerning Wright’s view of the birth narratives:
“Well-known problems abound [with the nativity tales about Jesus in the Gospels]. Why does the genealogy finish with Joseph if Matthew is going to say that he wasn’t Jesus’ father after all? This cannot have been a problem for Matthew or he would hardly have followed the genealogy so closely with the story of the virginal conception. It was enough that Jesus was born into the Davidic family; adoption brought legitimation. Further, anyone can say that Matthew made it all up to fulfill Isaiah 7:14 (‘the virgin shall conceive’). Since Luke doesn’t quote the same passage, though, the argument looks thin. Is Bethlehem mentioned only, perhaps, because of Micah 5:2-4? Again, Luke doesn’t quote the same passage, but still gets Mary to Bethlehem for the birth. Some have questioned whether Herod would really have behaved in the way described in Matthew 2; the answer, from any reader of Josephus, would be a firm yes.
“One can investigate, as many have, whether there really was a star. One can challenge the flight into Egypt as simply a back-projection from a fanciful reading of Hosea 11:1. These are the natural probing questions of the historian. As with most ancient history, of course, we cannot verify independently that which is reported only in one source. If that gives grounds for ruling it out, however, most of ancient history goes with it. Let us by all means be suspicious, but let us not be paranoid. Just because I’ve had a nightmare doesn’t mean that there aren’t burglars in the house. Just because Matthew says that something fulfilled scripture doesn’t mean it didn’t happen…
“Attention has focused on the census in Luke 2:2-whether it took place and could have involved people traveling to their ancestral homes. But Luke’s point has been missed. The census was the time of the great revolt-the rebellion of Judas the Galilean, which Luke not only knows about but allows Gamaliel to compare with Jesus and his movement (Acts 5:37). Luke is deliberately aligning Jesus with the Jewish kingdom-movements, the revolutions which declared that there would be ‘no king but God.”
“The census is not, of course, the only query that people have raised about Luke’s birth stories. Jesus’ birth at Bethlehem seems to have been a puzzle to Luke, which he explains by the census, rather than something he invents for other reasons. The fact that Luke does not mention the wise men, nor Matthew the shepherds, is not a reason for doubting either; this sort of thing crops up in ancient historical sources all the time. Of course, legends surround the birth and childhood of many figures who afterwards become important. As historians we have no reason to say that this did not happen in the case of Jesus, and some reasons to say that it did. But by comparison with other legends about other figures, Matthew and Luke look, after all, quite restrained…
“No one can prove, historically, that Mary was a virgin when Jesus was conceived. No one can prove, historically, that she wasn’t. Science studies the repeatable; history bumps its nose against the unrepeatable. If the first two chapters of Matthew and the first two of Luke had never existed, I do not suppose that my own Christian faith, or that of the church to which I belong, would have been very different. But since they do, and since for quite other reasons I have come to believe that the God of Israel, the world’s creator, was personally and fully revealed in and as Jesus of Nazareth, I hold open my historical judgment and say: If that’s what God deemed appropriate, who am I to object?”
N. T. Wright, “God’s Way of Acting,” The Christian Century, December 16, 1998, pp. 1215-17. http://www.religion-online.org/showarticle.asp?title=17