The "Virgin" Mary?

So why is it so important that she be a virgin, anyway? Two reasons, I reckon: so that there's absolutely no possible doubt that Jesus is in fact the son of God, and--more importantly, I'm thinking--because only a virgin is considered to be "pure" enough to bear mankind's redeemer. You've got to sort of admire Joseph's forbearance here, but it's hard to see how there wouldn't be a certain lingering resentment.

We are told that he "had no marital relations with her until she had borne a son," which isn't really a passage the fundies like to bring up, because they want her to have remained eternally virginal. But they lose! Ha ha! More importantly, though, we must ask ourselves: what would have happened if they had had sex while she was pregnant? I mean, presumably there was some reason for them not doing so, or why would they specify? Maybe they were just uncomfortable with the idea of pregnant sex; some people are, certainly. But my, superior, theory is that to do so would have knocked the divinity right out of Jesus. Somehow, the human sperm neutralizes the divine power. This is something that should probably be kept in mind if Jesus returns and you want to form a resistance movement, and aren't you proud of me for not making a "second coming" joke? Oops.