The reading for today is Matthew 1:18-25, which tells us of Joseph hearing of Mary being with child, as verse 20b says, "the child conceived in her is from the Holy Spirit." He had been planning on ending their betrothal, albeit quietly, but with this news, he took her in to his house.
The post-Apostolic era, even through the early Church Fathers, was rife with stories about who the father of Mary's baby might be. Many rumors suggested that Mary, far from being the pure child, had worked as a Temple prostitute and was pregnant with the child from some Roman. Other stories were that she was raped by a Roman soldier. From the very beginning, the claim of "virgin birth" was considered ridiculous, and stories swirled that attempted to paint the conception of Jesus in an apposite a light as possible.
Yet, reading this passage, as well as the story in Luke 1, about Mary discovering her pregnancy, really, to my reading, have little to nothing to do with, to be blunt, biology or gynecology, and everything to do with theology. That is to say, Mary's child was not the result of the Holy Spirit placing within her womb a fetus. Rather, the story is about the grace-filled workings of God in the life of this young woman.
Part of my problem with the doctrine, if one can call it that, of the Virgin Birth, is its inherent hyper-rationality. It seeks to understand the mystery of the incarnation through a consideration of our basic understanding of human reproduction. Jesus is the Son of God; Mary gave birth to him; therefore, there must have been some kind of Divine intervention at the very beginning, to place this child within Mary to grow and from which to issue forth. This crossing of the lines between a simple, almost logical consideration of the facts we understand concerning how we make babies, and an almost magical view of the workings of God has produced this odd, and to my mind irrelevant notion, that Mary not only was a physical virgin before her pregnancy, but continued to be so after. Despite the clear testimony of Scripture that Jesus was part of a family with siblings (including James, who, after Jesus' passing, became a leader of the Jerusalem Church), the Roman Catholic Church has stretched this idea to the non-Biblical notion that Jesus was the only child of Joseph and Mary.
We can get so caught up in insisting on the necessity of the Virgin Birth for an understanding of the incarnation that we forget that these stories aren't about sex. They are about Divine grace. There really is no way to understand "how" it came to be that Mary, a young unmarried Nazarene woman, came to be with a child that her parents seemed to understand was more than just a generous gift from God to them, but for the whole world. Beyond insisting that the Holy Spirit was at work even then in the lives of Mary, Joseph, and the fetal Jesus, I think it is enough to say that it happened.
Far too often talk about Jesus' birth get caught up in social discussions on everything from abortion and class attitudes toward pregnancy (particularly as it to relates to the institution of marriage), to our general cultural psychosis about sex. It would be nice to do away with the magical thinking, which - to my mind anyway - seems to carry an implicit idea that sex, particularly in the case of the parents of Jesus, is somehow wrong. Much better to think of a young, barely adolescent Mary, pure and holy, discovering that she is with child through the intervention of God and in no other way.
It would be nice if we could reclaim the marvelous divine gift of human sexuality within the context of the birth narratives. The old rumors and stories - was she a whore? was she raped? - are of little consequence at the moment. Rather, we might just consider the all-too-human idea that Mary and Joseph, like not a few couples, might have eaten of the fruits of the matrimonial tree before they were fully ripe, as it were. In saying that, I am not saying anything more than that Jesus parents were, just as our Church has claimed for close to seventeen hundred years for their first child, fully human.