Both the gospel of Matthew and the gospel of Luke note that Jesus's parents were Mary and Joseph. Both also narrate that Mary was engaged but not married to Joseph when she got pregnant. But the accounts of how they discover this startling news differ slightly.
- In Matthew's gospel, Joseph is so troubled when he finds out that his fiancée is pregnant that he wants to divorce her (back then, when two people were engaged, they were in a kind of contract, so a bill of divorce would have been necessary). Because he's such a good guy, he wants to break it off quietly rather than humiliate her in public. But before he can do that, Joseph receives a revelation in a dream that the pregnancy is God's work. The angel that delivers this revelation also says that this unusual birth fulfills Isaiah's prophecy that "the virgin will be with child and bear a son, and they shall name him Immanuel, which means 'God with us'" (in the Greek version of Isaiah 7:14; Matthew 1:18–25). Calmed by the angel's message, Joseph goes through with the marriage. To confirm that the child isn't Joseph's, the author says that Joseph didn't have relations with Mary until after Jesus was born (Matthew 1:25).
- Luke's gospel also portrays Mary as a virgin when she conceives Jesus. But this time, the angel comes to her (rather than Joseph), and tells her of God's plan before the conception. Like Joseph (and perhaps with even greater reason!), she's upset and wonders how in the world she could be pregnant; after all, she knows that she has never slept with a man. But the angel reassures her that God's behind it. Mary consents, saying, "May it be done to me according to your word" (Luke 1:26–38).
How much of this information is historical? Well, think of it this way: Historians call things facts only if they can be proven. The gospel accounts corroborate Jesus's parents' names and the unusual circumstances of his conception. But beyond that, you can't really demonstrate the virginal conception and the role of God in Jesus's birth. However, this doesn't mean that these events didn't happen or don't signify anything; it simply means that they can't be proven. What is historical, on the other hand, is that the authors of Matthew and Luke wanted to communicate something through these details. They tried to explain Jesus's unique nature, and the stories of the virginal conception were the best ways to articulate what they believed (that Jesus was the son of God and the heir to the promises to David).