‘Nature of Things' looks at how parenthood changes men's brains and bodies with ‘Dad Bods'

Winnipeg Free Press

06-06-2025

TORONTO – A new episode of CBC's 'The Nature of Things,' timed to Father's Day, explores some of the ways men's brains and bodies adapt to parenthood.
The episode titled 'Dad Bods' takes viewers across Canada and around the world to look at social and scientific elements of fatherhood.
The Canadian Press spoke with director Christine McLean about how the doc, available now on CBC Gem, came together.
CP: Tell me about the tone of the documentary.
McLean: I like to think that it's not just humorous, but it's warm-hearted… I think the most important point that came out of all this science, most of it quite recent, only in the last 20 years or so, is that we as humans, we have these incredible bodies that are so adaptable. And especially our brains. What the science is showing us is that given the opportunity, we all have the potential, whether we're male or female, to be great nurturing parents.
Dads become more empathetic than they might have been before they had children, but they also become experts in their own child. The part of the brain that's stimulated is the part that allows us to read social cues. And they really become very intelligent in terms of figuring out why a baby is in distress.
CP: Did anything you learned while making the documentary surprise you?
McLean: I did not know that a man's testosterone typically goes down after he has a child. It made a certain amount of sense because I think many of us notice that when a person becomes a parent, they become a softer, gentler version of themselves… I had no idea that that was linked to biological changes inside that person. That was the first surprise.
All men are impacted by hands-on care of children: grandfathers, uncles, adoptive fathers. If they're holding that child, they have those hormonal changes happening.
That was all new to me.
I think new to most people was the recent science about the benefits of what they call skin-to-skin care, which is common in Canadian hospitals. I remember noticing a few years ago friends would send me photographs of babies being held by their dads, and the dads would have their shirts off. And I'm thinking, what is happening in the delivery room these days? It puzzled me. Is this a weird new selfie that people are taking?
Little did I know that there's all kinds of physical benefits to that. The father's heart rate goes down, his blood pressure goes down, the baby is comforted.
But also the baby often will take in the good gut bacteria that can be on the dad's skin and it helps their digestive system. And who knew that? That was only discovered a couple of years ago. And we now know that for babies who are born via caesarean section, they don't get the gut bacteria from the mom that they get with a conventional birth. And yet, if dads practise skin-to-skin care, the latest science shows that their contribution to that baby's gut health is as robust as the mom's would have been had she delivered vaginally. It's extraordinary.
CP: The episode made me think about masculinity, and the conversations we're having around what masculinity means.
McLean: It wasn't one of my goals to delve into that, but watching it, you can't help but think about these things. I would say that anybody watching this documentary is not going to be left with the feeling that a good father isn't masculine. I think they're going to have the exact opposite feeling.
The book that inspired it ('Father Time: A Natural History of Men and Babies' by American primatologist Sarah Blaffer Hrdy) delves into that a little bit more.
There is this sense that if we are to give men permission or at least encourage them to be close to their children, that the changes that happen in their body result in a different kind of masculinity.
I'm not going to say it's less masculine… I think that there's kind of a new version of a hero that's evolving when it comes to fathering children. And I think today's heroes are the dads who get up in the night, the dads that change the diapers, the dads that worry about whether their children are happy. And I don't think that makes them less a man. I think it makes them a greater human being. And I think that discovering there was so much going on in the male body in a sense takes gender out of the equation.
CP: How would you respond to someone who doesn't like the idea of their testosterone level going down?
McLean: The fact that testosterone goes down, when that was discovered about 20 years ago, it attracted a lot of attention and led to this burgeoning field of science. And I can only assume that there was some concern about that on the part of men, because it's testosterone that allows men and women to build body mass. It leads to competitiveness, it leads to assertiveness. None of those things are bad. The thought of losing some of that, I can understand where somebody — particularly a young man — might not like thinking about that.
But anybody who watches this documentary will see that the rewards for being a hands-on dad are so great. Losing a little testosterone in the process is no big deal when you see the rewards, the bonds that develop with your child.
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We couldn't fit everything into the documentary, but what the data shows is, in addition to fathers living longer and having greater health, they have stronger marriages. They have better relationships with their kids.
We were focused on the dads, but if you were to look at the children, there are so many profound benefits to a child to having a hands-on dad, in terms of how well they do in school, how well their mental health is.
And I think that a good dad makes for a good family, and good families make for a great community, and there's just these ripples of positive impact from dads being as involved as they are today.
This interview was edited for length and clarity.
This report by The Canadian Press was first published June 5, 2025.