Mom Genes and Father's Day

How fathers help make mothers, and why making fathers is a harder task

On Twitter before Mother’s Day I did a lot of Glengarry Glen Ross-style selling of my wife’s new book as an ideal gift for the holiday. Now that Father’s Day is coming round I’m not going to pretend that Mom Genes is the ideal gift to get for the dad in your life: Not even Shelley the Machine in his prime could close that deal. But the book does have a chapter about the role of fathers in the biological making of a mother, and I do think that dads could profit from reading the book, so in the spirit of the soft-sell I’m going to offer a couple of observations.

The primary one is that the deeper you go into the biological substrates of motherhood and fatherhood, the easier it is to come back up with a dark or cynical view of the masculine role in human reproduction. That’s because the central mammalian adaptations, internal gestation and the breastfeeding that gives “mammals” their name, are good for safeguarding the next generation and establishing an intense mother-child bond — but for paternal involvement, not so much.

“90 percent of bird species equitably split child-rearing duties with their mates,” my wife notes, “as if someone had stuck a chore chart on the refrigerator … Our backyard is home to a pair of hawks, and I often gaze up at their biparental nest in silent salute.” (She didn’t mention that sometimes the juvenile hawks fly low across the backyard and nearly whack our kids with a captured squirrel.) But only 5 percent of mammal species feature any infant care from dads at all. In this sense, the grimmest feminist account of human patriarchy’s exploitation has nothing on the natural order for most mammals, where males literally use females as vessels to extend their genetic legacy and then walk or crawl or prance away.

Humans are different, exceptional among mammals, we fall in love and marry and raise families together — but we live with that exploitative legacy nonetheless, often without even noticing its power. Before reading Mom Genes, for instance, I thought of the placenta (to the extent that I thought about it at all) much the way I thought about the uterus: As part of the female reproductive system, something women generate to help nourish and protect their unborn child. But not so: The placenta is an organ of the fetus, with the same DNA, but unlike the fetus its creation isn’t a fifty-fifty proposition; instead it’s “imprinted” by the father’s genes, becoming effectively a paternal outpost inside the mother’s body.

And by outpost I do mean in the military sense. Here’s my better half, with an assist from Yale’s Harvey Kliman, explaining how the battle works:

… Technically speaking, “having a pregnancy is a big, big problem for a woman,” Kliman explains. It’s risky and nutritionally expensive, and the female body’s first answer is resistance: only a fraction of all pregnancies make it to term, in large part because the maternal immune system tries every trick in the book to attack the placenta in the first few weeks.

Meanwhile, the father—whether he’s sitting beside you rewatching Game of Thrones for the fourth time, or already decamped for Kokomo— is fighting for the pregnancy via his imprinted avatar, the placenta.

It’s messy but mighty, Kliman explains, expertly flipping the omelet, a blood clot dangling from his gloved thumb. The maternal side of the placenta, where it attaches to the uterine lining, is a hot mess, but the fetal side looks smooth, collected, and alien. “No matter how hard you twist this, you cannot compress the vessels,” he says, yanking the umbilical cord. Thick as the docking rope on a sailboat, it disappears into the placenta’s center.

I’d always thought of the cord as a lifeline that I’d flung out to my babies, but it’s the exact opposite. The whole placenta is like a grappling hook swung overhead and cast into the body of the mother. It branches into smaller and smaller hooks, or blood vessels, all designed to draw nutrition from the mom into the fetus. A mature human placenta has more than thirty miles of surface area.

Though it’s also called the “afterbirth,” the placenta starts to form extremely early, at just five days’ gestation, peeling off from the outside of the barely there fetal clump called the “blastocyst.” And almost immediately, this dad-driven sect of cells embarks on a coup d’état. Normally the pituitary gland, deep in a woman’s brain, sends signals to her ovaries to produce progesterone. (When the progesterone drip stops every month, her period arrives.) But in the very first days of pregnancy, the placenta bypasses the woman’s brain and takes the reins, messaging her ovaries directly for more and more progesterone, so that her pregnancy-preventing period never comes.

“The placenta says, ‘You know what, let’s do it my way,’” Kliman says, doing his best placental impersonation. “‘We can remove your head and still be fine.’”

Other maternal body parts go on the chopping block, too. Even your ovaries become irrelevant after about nine weeks or so, since by now the placenta has taken matters into its own “fingers” (that’s how Kliman describes the organ’s weedy internal structure, reaching deep into the woman). The placenta starts brewing up bootlegged progesterone in its own tissue, and components of estrogen, too, so that your ovaries can be surgically removed and the pregnancy will continue on its merry way.

“It’s kind of like when the space shuttle goes up from Cape Canaveral and about ten seconds into the air everything is taken over by Houston,” Kliman tells me. “The placenta is Houston. The pregnancy, through the placenta, takes over all operating systems of the mother.”

Meanwhile, the placenta ratchets up a mom’s appetite and thirst, even as placental hormones make it harder for her to access her own blood sugar. Three pregnancies’ worth of pad thai had, unbeknownst to me, bypassed my own liver to feed my husband’s placentas. Placental hormones also ready the breasts for nursing, prepping for a future when the baby’s nutrition will be delivered via milk instead of blood.

All of this baby-mama drama arises, in part, from one of those lingering difficulties with internal gestation, which is that a mammalian father never really knows for certain if a child is his. So, rather than provision the child from the outside at great personal expense, he has evolved ways to press his claims from within.

And because a man can’t be confident that he’ll ever have a shot at another kid with you, it’s also in his biological best interests to ransack your carcass for all it’s worth this time around and extract the biggest, healthiest brat possible. Despite his kind, twinkly eyes and habit of bringing home your favorite grain bowl unbidden, his genes want to take you to the cleaners.

Again, this is some seriously ruthless, Charles Darwin meets Andrea Dworkin material. And there’s this rather more visceral depiction of how the placenta goes to work:

Under a microscope, Kliman shows me a piece of a woman’s uterine lining that, to the naked eye, looks like a slice of fine prosciutto. With a ghostly white arrow he shows how certain placental cells—“They’re very aggressive,” he says—actually leave the placenta proper and migrate into the tissue of the mother, where they attack her arteries like starved wolves.

Setting sail a few weeks into pregnancy, these invasive cell bodies, which look like tiny black polka dots in the pretty pink paisley of the mother’s tissue, remind me of the thousand ships that the Greeks sent after Helen. There are far more than a thousand, though. Hundreds of millions of placental cells surge into the flesh of each pregnant mother. And they use military-style tactics that even Agamemnon might admire.

Once they’ve got the mother’s juicy little artery surrounded, they assault its wall and—in a process that may sound all too familiar to mothers—turn its taut muscle into pink mush, a first step in commandeering the mom’s blood supply.

Is there any compensating change or sacrifice on the part of the male, any way in which procreation works a transformation in our flesh? To some extent, yes: The biggest is one that is our testosterone levels drop when the baby arrives, priming us for a role in infant care.

But this priming, crucially, only happens if the man has already made the fateful choice to stick around, to be a father and not just a placenta-planter. Likewise some kind of paternal instinct, a male version of the “core pro-baby motive” that’s instilled by the maternal transformation, can be coaxed out of men, but it depends “on the amount of exposure that a man has to the mother of his child, and later, to the child itself.” If “new moms are hormonally primed to seek out experience with infants … new dads must have those experiences in order to get their hormones rolling.” The mere existence of a pregnancy and a child transforms a woman, but it takes active fathering to transform a man.

That choice to be transformed, and the sacrifices it entails, is good for us in many ways; obviously I think it’s the best choice a man can make. But in strict Darwinian terms it isn’t necessary, and while every human society places some sort of pressure on dads to be involved and stick around, there’s a lot of variation in the form that involvement, from de facto matriarchy to polygamy, and most societies have evolved ways to protect kids even in situations where the father doesn’t play a particularly active role. (Mom Genes notes that in many cultures “the presence of a nearby grandma seems to be more of a boon to a child’s survival” than the presence of a dad.) Historians and anthropologists and geneticists have interesting debates about the pre-history of the nuclear family, the extent to which it was invented in medieval Europe or has a deeper antiquity. But very clearly it’s not the only way to organize a human society, or an inevitable order somehow inscribed in the nature of procreation or mammalian gestation.

Which, to bring this post around to my own preoccupations, is one of the problems with the way that pro-family conservatives have talked about the failing order of “traditional marriage,” the declining norm of lifelong heterosexual monogamy that they are trying to prop up and defend. The Catholic-inflected language of “natural law,” in particular, while not actually an invocation of biological instincts and imperatives, could not help but evoke them in a society so shaped by Darwinian science. And to the extent those arguments were translated into popular forms of debate they mostly made it seem like conservatives were saying that the traditional family was “natural” in the sense of being dictated by our genes or hormones, which produced several obvious rejoinders: That all kinds of sexual behavior, including rape and promiscuity, are rooted in our biology, so why should we take “nature” as any kind of moral guide — that if we did take nature as a guide then there’s no reason to privilege bourgeois norms over all the other desires that people have instinctively — and that if lifelong heterosexual monogamy is really so natural then surely it’s also resilient, and why are conservatives so worried that it might somehow go away?

A better argument for conservatives (not a winning one, but a better one), I think, would have been to acknowledge that norms of lifelong monogamy are, in some important senses, un-natural — that they work with biological realities, including the realities described above, but that their aspirations and expectations are a civilizational artifice, a cultural superstructure that isn’t exactly necessitated by the substructures underneath. (The religious can interpret the development of marital norms in the Bible this way: As divine tutelage working on a fallen human nature that absent divine prompting constantly lapses toward, well, King David’s behavior toward Uriah and Bathsheba.) And that being un-natural in this way, these norms actually quite vulnerable and fragile to shifts in the human ecosystem — technological, economic and cultural alike.

This kind of argument would track, in a way, with the work of feminist historians like Stephanie Coontz, which casts companionate bourgeois marriage as a relatively recent invention rather than an ancient tradition. But rather than emphasizing the “inventedness” as a way of deconstructing and demystifying the institution, it would celebrate the invention, and treat the norm of lifelong pair-bonded fidelity as a fragile achievement that’s good for men and women and children (albeit in different ways) and whose egalitarianism (everyone deserves one spouse and two parents) undergirds a lot of the democratic norms that we take for granted in the West.

And then this conservatism would predict, or observe, that when this invented institution is culturally deconstructed and socioeconomically degraded, what you get overall is not necessarily an escape from socially-constructed exploitation into a more perfect freedom, but a renewed influence for some of the harsher, Darwin-meets-Dworkin biological realities that the institution of lifelong monogamy evolved to transmute or suppress.

So you get new patterns of dating that looked more Darwinian and anti-egalitarian than the prior dispensation, and that leave more people unhappy and alone. You get new social models of parenthood that “work” by requiring mothers to bear more burdens, not fewer, while taking for granted that the men in their lives will be simultaneously hapless and exploitative — a peculiar combination vividly illustrated in the working-class sociology of HBO’s “Mare of Easttown,” about which I hope to write next week. You get a freedom from social restraints in which the profound biological differences between how the sexes experience procreation become more important, not less — which in turn tends to sour men and women on each other, leading modern societies toward a strange sterility amid all their material abundance.

All of which is to say that going deep into the differences between mom and dad biology, and the ways in which mammalian paternity can seem like an act of raw physical exploitation — or an act whose significance ends with the act itself, leaving men vestigial to family life thereafter — should lead to a greater appreciation of everything human civilization does to make fatherhood a form of service, love and sacrifice instead. And we should hope that this fragile achievement will persist for as many men, and women, and their children as is possible, unto generations yet unborn.

Happy Father’s Day. (And, you know, buy the book.)