I can assure you that people 2,000 years ago knew the facts of life just as well as we do (and perhaps more so, since most of them lived close to the land and dealt with birth regularly, not just among people but among their animals). They knew that -- humanly speaking -- a virgin birth was impossible.
And yet the Bible is clear: Jesus Christ had no human father. When the angel came to tell Mary she would be the mother of God's Messiah, her immediate reaction was to wonder how it could possibly happen, since she was a virgin. The angel's reply must have stunned her: God's Spirit would be the Father of her child: "The Holy Spirit will come upon you, and the power of the Most High will overshadow you. So the holy one to be born will be called the Son of God" (Luke 1:35). Incidentally, the writer who recorded this account was Luke -- a physician.
Why is the virgin birth of Jesus so important? It's important because it tells us that Jesus was different from anyone else who'd ever been born, or ever would be born. He wasn't just another human being; He was the divine Son of God, sent from heaven to save us from our sins.
During this Christmas season, I invite you to turn your heart and mind to Jesus Christ as He is found in the Gospels -- who He is and what He has done for you. His miraculous birth points us to an even greater miracle -- the miracle of the new life God promises to all who open their hearts and minds to Christ's transforming power.