I recently saw Bill Maher's documentary and he mentions that the virgin birth is only mentioned in two of the gospels. He goes on to bug Christian people several times by asking questions such as "How can you believe in the virgin birth if it's only mentioned in two of the gospels?". I know for a fact that the virgin birth is mentioned in the gospels of Matthew (1:18) and Luke (1:26-35), however, it is mentioned in neither Mark nor John. In spite of that, millions of Christians world-wide take the virgin birth for granted. My question is, as stated above, why isn't the virgin birth of Jesus mentioned in all four gospels?
The birth of Jesus is also only mentioned at all in Matthew and Luke. Following the logic, since only half of the Gospels mention that means we should discard the theory that he was ever born at all.
In 100% of the cases where a birth narrative is present, the miracle of God becoming man is mentioned. Indeed, in John, even where the birth narrative isn't present, the incarnation - that God became man - is explicit.
Neither John nor Mark say anything about the birth of Jesus at all, so it is not surprising at all that there is nothing about the virgin birth.
The underlying assumption is that if something is true, it has to appear in all four Gospels. However, if it appeared in all four gospels, some would ask why doesn't it appear in every epistle as well.
It's interesting that people attack the Bible for having four versions of the same story in the Gospels and other people attack the Bible for not having four exact copies of the same story in the Gospels. Some people will find fault no matter what the Bible teaches.
A good answer to bill maher's question would be to ask him if he believes that Jesus died and rose again from the dead, since that is, in fact, recorded in all four gospels. Of course he would say he does not, because he doesn't believe the Bible. By the same token, those who believe that Jesus did die and rise again are well prepared to believe that Jesus is also virgin born, even though only two gospel accounts record that. One witness would have been sufficient--two is more than enough.
Mark and John, as Affable Geek noted, do not even record Jesus' birth. The books were written to concentrate on different aspects of Jesus life.
So, maher's question was nonsensical at its very root.
why isn't the virgin birth of Jesus mentioned in all four gospels?
Because mentioning it wasn't important to Mark or John.
It's really that simple. The writers of the Gospel accounts & the epistles weren't trying to mention everything that's true. They weren't even trying to mention everything that matters.
Maher's attempt to turn this into any kind of argument is pretty silly. (Affable Geek and Narnian say more about that.) I'm afraid I can't understand how anyone can see his question "How can you believe in the virgin birth if it's only mentioned in two of the gospels?" as anything but an obvious non sequitur. It's reaching & empty rhetoric, not rational skepticism.