Short response: I agree with McGrath that Matthew’s story is unlikely to be historical. Miraculous birth narratives are such a common trope in ancient literature that anytime you see one you should be skeptical, and the conflicts with Luke should force any critical reader to take a second look.
Anyway, I learned about the historical issues with Matthew’s account in a freshman Bible course, so I’m a little surprised there’s any fuss.
It’s commonly noted that the story of the Massacre of the Innocents is similar in many ways to the story of Moses’s birth in Exodus. One thing that commonly gets lost in this discussion is the greater similarity between Matthew’s account and the version given by Josephus in his The Antiquities of the Jews.
Josephus wrote Antiquities in order to explain Jewish lore and history to his greek audience. He begins his account with this promise:
As I proceed, therefore, I shall accurately describe what is contained in our records, in the order of time that belongs to them; for I have already promised so to do throughout this undertaking; and this without adding any thing to what is therein contained, or taking away any thing therefrom.
… he then proceeds to diverge quite a bit from the stories we see in the Hebrew testament. The basic structure is the same, but there are significant differences, including the birth of Moses. According to Josephus, while the Israelites were under the thrall of the Egyptians, the Pharaoh heard a prediction from one of his scribes:
One of those sacred scribes, who are very sagacious in foretelling future events truly, told the king, that about this time there would a child be born to the Israelites, who, if he were reared, would bring the Egyptian dominion low, and would raise the Israelites; that he would excel all men in virtue, and obtain a glory that would be remembered through all ages. Which thing was so feared by the king, that, according to this man’s opinion, he commanded that they should cast every male child, which was born to the Israelites, into the river, and destroy it …
A man whose name was Amram, one of the nobler sort of the Hebrews, was afraid for his whole nation, lest it should fail, by the want of young men to be brought up hereafter, and was very uneasy at it, his wife being then with child, and he knew not what to do. Hereupon he betook himself to prayer to God; and entreated him to have compassion on those men who had nowise transgressed the laws of his worship, and to afford them deliverance from the miseries they at that time endured, and to render abortive their enemies’ hopes of the destruction of their nation. Accordingly God had mercy on him, and was moved by his supplication. He stood by him in his sleep, and exhorted him not to despair of his future favors…
So here we have a visitation from God, assuring Moses’ father that the little tyke shall live and grow up to kick Egyptian butt:
Know therefore that I shall provide for you all in common what is for your good, and particularly for thyself what shall make thee famous; for that child, out of dread of whose nativity the Egyptians have doomed the Israelite children to destruction, shall be this child of thine, and shall be concealed from those who watch to destroy him: and when he is brought up in a surprising way, he shall deliver the Hebrew nation from the distress they are under from the Egyptians. His memory shall be famous while the world lasts; and this not only among the Hebrews, but foreigners also:—all which shall be the effect of my favor to thee, and to thy posterity. He shall also have such a brother, that he shall himself obtain my priesthood, and his posterity shall have it after him to the end of the world.
So we have the slaughter of innocents as an attempt to kill the “chosen one,” and we have the divine visitation. Both of these are in Matthew’s birth narrative, but neither are in the Exodus version of Moses’ birth.
Antiquities was written around 93 CE, in about the middle of the range in which Matthew’s gospel is believed to have been written. It’s possible that the author of Matthew had access, but it seems more likely that they were simply both drinking from the same well of Jewish tradition.