Understanding the issues with the virgin birth

We are closing in on yet another (war on) Christmas day, and it brings with it a number of implications. Most notably, the idea that a young woman in a small village somehow became pregnant, not by her husband, but by a deity.Of course, most people who do not subscribe to the faith are sure to cry "foul"on this claim. And who wouldn't? On the surface, there are a number of more likely explanations. Maybe she (the figure Mary) had premarital intercourse with her soon-to-be-husband (Joseph). Or...