The Science Behind the Virgin Birth

Although the religious meaning of Christmas was long ago neutered, replaced with the secular joys of eggnog and mall Santas, at its core December 25 is still a celebration of Jesus Christ's virgin birth. Although holy men have long regarded the virgin birth as an inexplicable miracle, others have sought scientific explanations for the story—either to prove its plausibility or debunk it as an impossibility. These seekers have come up with several intriguing, and conceivable—if improbable—scientific explanations.

Before jumping into the science, it's worth clarifying what we mean when we talk about the "virgin birth," a term that's frequently contested and often confused with the immaculate conception. Many have argued that the prophecy of Christ's birth in Isaiah 7:14 uses the Hebrew word almah, which means a young—but not necessarily virginal—woman. This, some argue, could have been mistranslated as "virgin" by hapless Greek scholars over 2,200 years ago, creating a false mythology. But even if the prophecy was mistranslated, the tales of Jesus's birth in the gospels of Matthew and Luke are emphatic that the savior was born of a virgin woman.

Still, it's not clear what virginity meant during the time of Jesus—just like it's not entirely clear what virginity means today. An intact hymen? No history of penetrative intercourse? A total lack of exposure to sexual stimulation? It's too easy to explain a "virgin birth" if virginity just meant an unbroken hymen, or lack of vaginal intercourse—maybe semen leaked in during dry humping; or maybe Mary was sexually active, but still had her hymen intact. So we should use the most conservative definition of virginity—total abstinence from sexual activity—to provide an airtight scientific explanation for Mary's virgin pregnancy.

With that assumption, the go-to scientific explanation for the virgin birth has long been that Mary somehow achieved human parthenogenesis, a process by which some animals reproduce without mates. In parthenogenesis, a cell within an animal splits via meiosis, halving its genetic material. Then one of these split cells, essentially an egg, fuses with another split cell nearby, fertilizing itself and—because the genetic material of cells were not split evenly or identically—creating a not-quite-clone embryo that can be carried to term.

Parthenogenesis is common in invertebrates; birds, fish, and reptiles can have virgin births as well. Until recently, scientists believed this was a rare response to captivity, environmental stresses, or mate scarcity, but over the past three years, researchers have found that parthenogenesis is also surprisingly common in healthy populations living in the wild. And while researchers are still trying to figure out what triggers parthenogenesis, the fact that it happens across so many species means it's theoretically possible that Mary could have given parthenogenetic birth to Christ.

But the hypothesis is still shaky, because while mammals can initiate parthenogenesis, they typically cannot give parthenogenetic birth. A mammal's eggs usually split to accommodate the DNA in sperm when they sense the swimmers getting close, then die off if fertilization fails. Trickery, or random genetic irregularities, can cause a split in the absence of sperm and even recombination with another nearby split cell—but mammals (with the exception of echidnas and platypuses) use a process called imprinting to make sure reproduction only kicks into gear with the right complementary match of active and inactive genes between sperm and eggs of the same species. So if parthenogenesis begins, it creates a haywire oddity that doesn't survive beyond a few days.

There are ways to overcome this problem. In 2004, Japanese researchers showed that they could alter imprinting genes in mouse eggs to create an artificial but fully parthenogenetic and viable baby. It's possible, if extremely unlikely, for these same genetic alterations to occur as random, natural mutations. But genetic mutations that overcome imprinting alone would have meant that Jesus only received X chromosomes, from Mary, making him a her.

In her 2012 book Like A Virgin,science writer Aarathi Prasad offers a couple workarounds. One possibility, Prasad theorizes, is that Mary could have been a genetic chimera—meaning, formed from both male and female embryos—which would have meant she had Y chromosomal material that could have been absorbed into her theoretically self-created Christ child. Alternatively, Prasad offers, Mary could have been intersex—having both female and male genetic characteristics. Specifically, she could have been born with ovotestes, a condition in which a woman gets an X chromosome from her father that contains a sprinkle of Y chromosome, leading to the development of a hybrid ovary-testes organ. If Mary only manifested her male material in her gonads and, again, had a perfect balance of masculine and feminine tissues and hormones, her ovotestes could have produced sperm and eggs simultaneously, sending them down the fallopian tubes together, and resulting in fertilization and implantation within her functional uterus.

It's tempting to write this off as functionally impossible, but there's been at least one recorded case of a girl born with a possibly suitable balance of genes and genetic expression for this self-fertilization to play out—in Mexico, circa 2000. Researchers are still waiting to see if the child would be able to produce viable sperm and eggs, and thus produce a virgin birth.

There's at least one simpler explanation for the virgin birth, although it's brutal and very messy. According to a 1988 report in the British Journal of Obstetrics and Gynecology, a 15-year-old girl in Lesotho who had been born without a vaginal opening (due to a condition known as Müllerian agenesis syndrome) gave birth to a healthy male child via C-section. While giving her beau a blow job, an ex had walked in on the woman, pulled a knife, and stabbed her twice in the abdomen, allowing the sperm in her empty stomach to leak through her damaged gastrointestinal tract and into her reproductive system.

Although many have been skeptical of this account, urologists believe it's possible, as sperm can survive acidic environments, travel further than we appreciate, and survive in friendly environments for days, fertilizing eggs even outside of their traditional meeting places. And while someone with Müllerian agenesis would usually have trapped menstrual blood blocking up her uterus, it wasn't an issue in a young girl like this one.

Obviously, this scenario is extremely grim, in contrast to the pure life Mary supposedly lived. But the conditions need not have been the exact same. If Mary had suffered a non-fatal abdominal wound (or even had a peculiar abscess) in the presence of semen, then there's a chance—however slight—that she could have been crudely impregnated, without any sexual act.

So a virgin birth is scientifically possible, though it's so highly improbable that most scientists don't put much stock in the idea.

"I have been asked [about the virgin birth] many times," said Warren Booth, a leading expert in parthenogenesis at the University of Tulsa, "and honestly I can come up with no feasible explanation as to how a female that had abstained from intercourse could give birth to a child of either sex."

To devout Christians, of course, it doesn't really matter if the virgin birth is scientifically unlikely, because science is a discipline exploring the laws and nature created by God. "God is not a captive of the universe," said Vern Poythress of the Western Theological Seminary, an evangelical theologian whose work focuses on the divine truth and authority of the Bible.

Poythress uses his background in math and science to dissect and dispute rationalist arguments against faith. As for God's role in the virgin birth, he explained, "He's not caught in a system of impersonal law. He's the lawgiver. He's the author of both the regularities and the things that are exceptional…. He can do unusual things when it suits him."

The way Poythress and others see it, God could have created a sperm with a Y chromosome from nothingness, or from the atoms in the Virgin Mary's womb as needed, fertilizing her egg and creating a wholly human, but also wholly divine, genetic male. Of course, Poythress doesn't have proof that God went about Christ's conception that way, but that's beside the point.

"The Bible is not getting into all the technical details," he said. "God knows all the technical details. But His purpose in the Bible is not to satiate modern scientific curiosity, but to tell us what we really need to know from the standpoint of salvation, from the standpoint of our personal understanding of ourselves and our relation to God."

Unlike some Christians, who sometimes violently reject the search for scientific explanations of the virgin birth, Poythress acknowledges that it's almost impossible to distinguish between divine acts and those that extend from God's orderly laws of nature. Still, he doubts that there is a scientific explanation for the virgin birth, and rejects the idea that this disproves it in any way.

This is fair—those who criticize magic, mysticism, and even faith from a rational perspective often forget that a lack of evidence is not proof of something's falsehood. They also forget that God and his works stand outside of the realm of firm scientific inquiry or disproof.

So whether people come up with complex scientific explanations, or reject those explanations as impossible, the virgin birth of Christ will likely always remain a mystery. And in a debate wrapped up in faith, which transcends science or rationality, neither assertion really matters.

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