This Is Your Brain on Fatherhood

Fourteen years ago, when I decided to become a stay-at-home dad, I didn’t think it was that big of a deal. Sure, I knew that switching our assigned roles was a Controversial Thing. But because of our unique set of circumstances, it just worked. And so I leapt headfirst into the world of active fatherhood—diaper-changing, boo-boo-kissing, bedtime-story-reading, bath-giving, toilet-training, that sort of thing. I was an uncivilized brute in no-man’s land. And over the years, I became Mrs. Doubtfire, Daddy Daycare, school bus driver, and the big dog of the playground. Papa for short.

The macho man in me thought that I could always undo this Controversial Thing, get a regular job, and return to the way things were as the designated Bringer-Home-of-the-Bacon. Boy, was I wrong. Years later, as a father to three boys (two teens and one tween), I find that I’ve transformed into something strange. I have metamorphosed into something Other. A creature set apart from my career-driven peers. A weirdo who takes pride in meal prep. A WFH dad who sneaks house chores into status meetings. A father who knows his children and whose children know him. And the weirdest thing of all? Some of these Bizarro changes are even biological. Yes, according to science, active fatherhood changes your hormones and your brain. I can verify that this is true.

Today, stay-at-home dads—or even active fathers—aren’t such a Controversial Thing anymore. Economic realities mean both parents often have to work and share childcare duties. These days, I see lots of dads at school or in the parenting group chats. Still, I’m aware that some people have objections and strong feelings.

Men aren’t built for taking care of kids. That’s the most common line. Men are providers. Full stop. We’re just different, they say. Not equipped. Incompetent. Or so the old thinking goes.

Where this thinking comes from is the subject of another essay altogether, but a growing body of science contradicts the established belief. It turns out, just as motherhood changes women physically, hormonally and mentally, fatherhood does the same. To put it simply, men are made for active fatherhood.

Preparing to be a father begins long before the baby is born—and your body knows it. If you spent the months before the baby’s arrival reading articles, or if you obsessed over buying the perfect crib and the perfect baby carrier, there’s a reason for that. It’s your body preparing you for fatherhood.

Even before the baby is born, fathers experience a drop in testosterone—a hormone responsible particularly for sex drive and strength—in preparation for a new care-driven role. While women experience dramatic changes during pregnancy, their male partners are simultaneously undergoing subtle, quiet changes of their own.

Even more fascinating: this isn’t just a male thing or a human thing. Research from primatologist Sarah Blaffer Hrdy shows that it’s a primate thing, even a mammalian thing. So the next time you hear some man say they’re “not built that way,” kindly tell them that they’re dead wrong.

This drop in testosterone continues when the baby is born. When new fathers hold their babies for the first time, their testosterone and cortisol levels—a hormone related to stress levels—drop, researchers Kuo, Braungart-Rieker et. al. discovered.

Meanwhile, anthropologist Lee Gettler studied this drop, finding that men with babies had much lower levels of testosterone compared to men who weren’t fathers (coincidentally, in a study in Cebu City).

What’s more, when fathers engaged in active fatherhood, their testosterone levels dropped further.

Here’s what got a big “Wow!” from me: It wasn’t just being a father that lowered testosterone levels. The researchers found evidence that engaging in childcare showed even greater drops in testosterone. Another factor in lower testosterone levels? Sharing a bed with their infant.

I stumbled into active fatherhood almost by accident. When my first son was born, he had trouble regulating his temperature, and we spent many hours sharing warmth through skin-to-skin contact. Underneath the hood, so to speak, not only were my testosterone levels dropping, but my brain was also rewiring itself for fatherhood.

Researchers published in Traditional Psychiatry discovered that the brains of new fathers actually shrank and then grew in other parts. In the first 12 weeks after childbirth, fathers’ gray matter volume decreased in brain regions involved in attention, sensory processing, and decision-making. According to the researchers, these changes help the brain to become more efficient.

After the shrinkage, in weeks 12 to 24 after birth, other parts of the brain started to grow, the researchers found. The biggest growth happened in parts of the brain that involved anticipating tasks and dividing attention—clearly beneficial for parents taking care of those fussy newborns.

As more and more research piles on, it’s becoming clear that a rethinking of fatherhood is overdue. Stay-at-home dads, or active fathers, are not the flipside of feminism in a world gone topsy turvy. Men are built for fatherhood. Our physiology says so. Our brains dictate it. Yes, we provide, we protect. That’s still there, and no one took it away. But we are beginning to discover that we aren’t, in fact, the resident silverback gorilla who is on a hair-trigger for sudden violence. Dads also nurture, we also provide care. It’s natural, it’s wired into us, get over it.

Let me end this with a story. This year, for my second son’s 14^th birthday, he turned down a steak dinner in a fancy restaurant for “Dad’s Legit Italian Carbonara.” It gave me pause because, growing up, birthday meal requests always belonged to my mother; it was her specialty, her pride, and her gift. And now it’s mine.

In another surprise, for father’s day later this month, my second son has independently decided that he will cook Dad’s Legit Italian Carbonara himself, returning the favor for his old man. I’m not quite sure how this happened. In all honesty, I didn’t do it on purpose, but somehow the new generation has learned that provision and care aren’t separate gender-specified roles. They go hand-in-hand, and both are full of joy.