Probably important to remember that:
a) the early church, perhaps particularly Matthew's Gospel, had a need to prove that Jesus WAS the promised Messiah (even if this required some re-visioning what it meant to be the Messiah)
b) for the first few decades the early church was largely made up of Jewish followers of Jesus
c) the virgin birth idea seems to be a later addition to the tradition, most clearly expressed in Luke (John on the other hand has Jesus as the Word which has been around for ever and never touches on the practicalities of how the Word became flesh) with the story of the Anunciation. One could say that Jesus was God Incarnate and not require divine impregnation.