Was Jesus born of a virgin?

The earliest writings in the New Testament do not even mention Mary, the mother of Jesus. There is only one mention of the name, Mary, in Paul's letter to the Romans (Rom 16:6 - "Greet Mary, who bestowed much labor on us. ") . But there is no reason to believe that this was Mary, the mother of Jesus. There is certainly no mention of a virgin birth.

The author of "The Gospel According to Mark" was the next of the New Testament books to mention Jesus' birth. He only mentions Mary, the mother of Jesus 3 time: once in Mar 6:3 - "Is not this the carpenter, the son of Mary, the brother of James, and Joses...", then possibility again in Mar 15:40 - "There were also women looking on afar off: among whom was Mary Magdalene, and Mary the mother of James the less and of Joses, and Salome;" and in Mar 15:47 "And Mary Magdalene and Mary the mother of Joses..." Again, there is no mention of the virgin birth.

It is not until the author of "The Gospel According to Matthiew" writes, after 80 AD, that we see a very brief virgin-birth story for the first time! Finally, the author of “The Gospel According to Luke” writes the familiar nativity story that we're accustomed to seeing reenacted at Christmas time. So far, we see the story develop from:

• Paul: no mention of Jesus' mother or his birth
  
• Mark: only a brief mention of the Mary, no virgin birth
• Matthiew: finally, a brief story about the virgin birth
• Luke: full blown birth story

But why would the authors of the New Testament invent a story like a virgin birth if it didn't really happen? First, they didn't have to make it up. They may have simply borrowed from other ancient mythologies which also had stories about virgin births to prove the authenticity of their gods. For exampe: Perseus was born of the virgin, Danae. Dionysius was born of the virgin, Semele, who was impregnated by Zeus with a bolt of lightning.