The virgin birth is often ridiculed by scoffers for being impossible. Now, of course, the natural response from a Christian perspective is that the fact that the virgin birth is impossible from a natural perspective is the entire point. In other words, if the virgin birth occurred, it had to be a direct act of God. Consequently, they are completely missing the point. However, as long as God is involved in the process, it turns out that it is genetically possible. In fact, there are several ways that God could have accomplished it.
The first thing that we need to note is that such births, called parthenogenesis, sometimes occur in animals. In fact, it is only in mammals that it never happens naturally, and artificial triggering is never successful in producing a live birth. On the flip side, all types of this process are quite common in insects.
There are actually three common types of parthenogenesis. Now, while they provide examples of what God could have done, none of them could have naturally occurred in Mary, and they would have only produced a female baby.
Apomixis (Clonal Parthenogenesis) - In this case, no meiosis occurs, and the resulting child is simply a clone of the mother.
Automixis (Self-Meiosis Repair) - In this case, meiosis occurs but repairs itself by combining maternal chromosomes, resulting in a daughter that is not quite a clone, but likely to suffer from inbreeding problems.
Hybridogenesis (Semi-Parthenogenesis) - This is a case where the paternal genome is discarded, and only the maternal genome is passed on. This results in a child that has only one set of chromosomes, where the organism normally has a pair of each chromosome.
Now, none of these, of course, is a perfect match to the virgin birth, but they give possible ways for God to have brought it about. Automixis can be ruled out because of the problems that it would cause. However, apomixis and hybridogenesis offer possible clues.
One possibility would have been that God could have used an egg cell from Mary, were no meiosis had occurred, with God substituting a perfect male chromosome for one of Mary's X chromosomes. He then could have had the now fertilized egg start dividing as normal. One downside to this is that it would have resulted in Christ effectively being a male clone of Mary. In other words, he would have had all of her genetic defects and simply would have had a perfect Y chromosome. While hypothetically possible, the fact is that whenever this is artificially triggered in mammals, it never produces a live offspring. Now, grant you God could easily have done what scientists cannot, but this still would have its problems, Such as all of the mutations that Mary would have had after approximately 4,000 years since Adam and Eve.
Another possibility is that God could have taken one of Mary's unfertilized egg cells that had undergone meiosis. He then could have added a perfect Y chromosome and started the now fertilized egg cell dividing as normal. While it is popular among some Christians, this approach has its problems because it means that Jesus would not have had the normal redundant set of chromosomes. This would easily have caused problems from there being no backup genes to handle mutations. Furthermore, you would still have the problem that the effort to trigger this artificially in mammals has always failed.
Fortunately, there is a third alternative that is hinted at in both of the other two. In both of the other possibilities considered, because Mary was a woman, to produce a male child by virgin birth, God would have had to add a Y chromosome. So, as long as God was creating a fresh and perfect Y chromosome, adding in a fresh copy of the rest of the genome so that Jesus would have the same chromosome pairs as all humans do, simply makes sense.
This approach has two major advantages. The first is that it would provide Jesus with at least one perfect set of the human genome. The second is that it would be added directly by God the Father, which would add more literalness to Jesus being the Son of God.
In conclusion, while there are natural possibilities for a virgin birth, none of them work in mammals. Furthermore, none of them actually makes sense when done by divine action. This is because, at the very least, it would require the creation of a Y chromosome. The most reasonable solution is that God the Father created a new, perfect set of human chromosomes that he added to Mary's egg to fertilize it. This is a case of science providing us with some interesting Insights into the birth of Jesus Christ.
