Can a Virgin Give Birth?
Yes—but it’s very, very, very, very unlikely.
Yes, in theory. However, a number of rare events would have to occur in close succession, and the chances of these all happening in real life are virtually zero. For a virgin to get pregnant, one of her eggs would have to produce, on its own, the biochemical changes indicative of fertilization, and then divide abnormally to compensate for the lack of sperm DNA. That’s the easy part: These two events occur in the eggs or egg precursor cells of one out of every few thousand women. But the egg would also need to be carrying at least two specific genetic deletions to produce a viable offspring.

An egg will only start dividing once it senses a spike in cellular calcium. This normally occurs as a result of a sperm’s entry during fertilization. But if the egg happens to experience a spontaneous calcium spike, it will start reacting as if it’s been fertilized. A defective sperm that lacks DNA can produce a spurious calcium spike. In the lab, scientists can coax unfertilized eggs into beginning the post-fertilization process by simply injecting them with calcium.

Once fertilization—or faux fertilization—occurs, an egg can complete the final stage of a cell division known as meiosis II, during which it loses half of its genetic material to make room for the sperm’s DNA. But if there’s no sperm, each half of the divided egg cell will end up short, and both will die. In order for our virgin birth to proceed, the faux-fertilized egg must, therefore, not complete meiosis.
So, while it’s possible for a human baby to be born of a virgin mother, it’s very, very unlikely: These two genetic deletions might each have a one in 1 billion chance of occurring, and that’s not counting the calcium spike and division problem required to initiate parthenogenesis in the first place.