How do you answer pagan 'virgin birth' myths that resemble the Gospel?

Joseph and Mary went to Egypt, and while there they may well have told people where Jesus came from, that Mary was a virgin and the Holy Spirit had brought about His conception. Imagine that story traveling around Egypt, and some religious man saying, that sounds good, let us say one of our gods came from a virgin. That happens all the time. Many nations around the Jews, and the Gnostic writings, produced perversions of the gospel; there are over two hundred pseudepigraphal and apocryphal New Testament books making up fantastic stories to look superior, out of infatuation, jealousy, or competition, and the early Fathers had the job of sifting them down to the twenty-seven inspired books. It is the same with the flood stories that permeate Mesopotamia and beyond, about two dozen of them, each telling of one man and his family in a boat while the world is destroyed. Men copy other men's religions because they have none of their own to speak of. So do not be enamored by similarities; that is exactly what we would expect.