It has been argued that a virgin birth is possible in humans, just not common*, through parthenogenesis (ie. reproduction from an ovum without fertilization, which occurs normally in some invertebrates and lower plants). Would this mean that Jesus' birth was not miraculous and not the only virgin birth?
Answer: There has never been a 'natural' parthenogenetic birth in humans, because of all the complex errors that would have to happen to result in a 'normal' foetus with no father. And such a baby would probably suffer severe deformity.
Any baby resulting from a natural parthenogenetic birth would have to be female, because the mother has no Y chromosome to pass to her offspring. Therefore, the fact that Jesus was male is proof that it was not a parthenogenetic fertilization.•
* Slate.com (http://www.slate.com/id/2179865).