As for the virgin birth, well answer me one simple question. If it's irrelevant, why is it in the story in the first place and why are we going to be regaled with the assertion all over the next few tedious weeks as we run up to Christmas? You know full well why it's in the story. It's because the story needs Jesus to be set apart as someone a bit more special than everybody else, the possessor of a uniqueness. You can't just tell us that he's unique, you have to prove it by giving him magic powers, and the virgin birth was just the start!

Not quite that simple. The Koran also asserts the virgin birth of Jesus but doesn't ascribe superhuman powers to him.