you've discovered something about the

brain I think is quite surprising.

>> So we found that in fathers the brain is

actually shrinking and I'll explain why

but also there are studies that find

that both men and women who report

having had more kids have markers of a

younger looking brain age and then also

typically men when they do this show

[music] about a 25% drop in

testosterone.

The next studies of single women have

found that, you know, if you show them a

series of body types, the dad bot is the

most popular

>> and that's proven by science. So, if I

go out and get a dad bot, you're telling

me the science that says I'm going to be

more attractive.

>> Yeah, go for it.

>> See what my fiance says. The other thing

that's worth talking about is [music]

Have you done any studies on that?

>> Yes. That is one of the most robust

findings [music] in parenthood research

and my lab found actually that

>> Wow. So, I've always been really

interested in [music] families and

becoming a parent is one of the biggest

transformations that you can experience,

but I'm concerned about the declining

birth rate. And I think that we've

managed to market it as an undesirable

choice.

>> According to the CDC and Pew Research

data, [music] the US total fertility

rate just hit an all-time recorded low.

>> Yeah. I mean, the transition to

parenthood can be really challenging.

You are sacrificing yourself. It [music]

can be very isolating. You're losing

your sleep. But becoming a parent, you

are benefiting from this sense of

connection [music] and purpose. You will

rediscover your priorities in a way that

will ultimately bring a lot of value.

>> So if all goes well, next year I will

[music] be a dad and I would like you to

give me some advice on becoming a father

based on all the research that you have.

>> So great fathers are made not born.

There's a lot you can do. [music]

>> I'm going to write it down.

>> Love it. So first,

>> this is super interesting to me. My team

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I'll make sure every single week, every

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Please help us. Really appreciate it.

Let's get on with the show. [music]

Dr. Darby Saxby, you've discovered

something about the brain that I think

is quite surprising to a lot of men and

women as it relates to what happens to a

man's brain when they become a father.

Um, and I've got the report here in

front of me, but I have a model brain

over there. Could you explain to me what

exactly it is that you discovered?

>> Yes. So we found that in fathers and

this is similar to what's been observed

in mothers, the brain is actually losing

gray matter volume. So it is shrinking.

So if I had stronger hands, I could

probably squish this brain and make it

look tinier.

>> But the parts of the brain that are

shrinking the most are in what we call

the mentalizing network. And that's a

part of the brain that helps us

understand other people's feelings and

intentions. Those areas are kind of

concentrated around the midline of the

cortex, which is kind of what we're

seeing here. And then you also see

volume reduction in the visual areas,

which is the back of the brain, which is

really important for understanding when

you look at an infant's face, what kinds

of emotions it's trying to tell you. And

so we see changes to those parts of the

brain and new dads. In moms, we see

changes to these same parts of the

brain. We also see changes in moms to

what's called the subcortex, which is

this part of the brain that kind of

controls our gut feelings and our sense

of reward and is really strongly linked

with our hormones. So moms are kind of

changing all across the brain. Dads are

mostly changing in this top layer, the

cortex, which kind of controls our

higher order thinking, reasoning, and

executive functioning. And that tells us

something about fatherhood, which is

that fathers choose to engage in

parenting. It's a sort of cognitively

mediated investment that dads are

making.

>> What does that mean?

>> So, if you think about a mom who's been

through 9 months of pregnancy, she is

flooded with hormones when her baby is

born and she has a really high

investment in the baby's survival. Just

thinking about the number of calories

that it takes to sustain a pregnancy,

it's thousands. And and so there's a

very high floor from maternal

investment. And moms are undergoing

plasticity all across the brain that

reflects that. In dads, there's a

tremendous amount of cross-cultural

variability. So there are cultures in

which dads participate in child care and

are very hands-on with babies from the

moment of birth. There are cultures in

which there are prohibitions against men

picking babies up.

>> You don't pick babies up in the first

year. In some cultures,

>> you don't pick babies up because it's

considered unmanly. Okay?

>> So, there's a tremendous amount of

variability and dads calibrate their

investment according to what the culture

says and what the context looks like. If

mom becomes unavailable, dad is often

needed to step in and provide more of

the care. And so this sort of top layer

of brain changes reflects that, you

know, dads are modulating their

investment depending on what they're

learning from the environment. And the

word that biologists use for this is

facultative. So a facultative

adaptation is an adaptation that is

optional but extremely useful. You could

think about an animal that walks on four

legs suddenly having something really

important to grab and switching to walk

on two legs so that it can use its

hands. Hands are really useful for that

animal. Fathers are really useful for

humanity.

>> But are you saying they're optional,

>> but they vary depending on situation.

And I don't want to say that fathers

aren't important. They're incredibly

important. There are dads who are

primary caregivers and even sole

caregivers of children. But dads vary

and they vary depending on what is

needed for children to thrive in their

specific local context.

>> And a woman's brain shrinks as well, but

it shrinks a little bit more.

>> Yes, it covers more of the brain

>> and it also shows a larger across the

board volume reduction. And I should

explain volume reduction. We often think

about deficit mommy brain. you're

forgetting things. Volume reduction is

not a bad thing. What it means is that

the brain is actually working more

efficiently because it's building better

connected pathways and better channels

for communicating information.

>> Is it accurate to say that the brain is

focusing?

>> Yes, exactly. So, it's reshaping in a

way that enables more efficient

communication. It's learning. It's

consolidating. So, it's kind of like if

you think about the director's cut of a

movie that has lots of interesting extra

scenes and characters and then you watch

it in the theater and it's like this

lean mean 2hour cut,

>> right? Like many of us prefer the

theatrical release because it's easier

to follow.

>> And by getting rid of certain parts of

the brain, that means more energy can be

used in the other parts of the brain. Is

that broadly accurate?

>> Exactly. So that we're better able to

focus on what matters. And when we

become parents, what matters is our

children and the inputs they're giving

us.

>> The interesting thing is the way that

you described the part of the brain that

the man loses when they become a father

made it seem like they're losing

empathy.

>> No, they're actually improving in their

empathy because they're becoming more

efficient processors of social

information. So the fact that where we

see the biggest changes are in these

what we call mentalizing social

cognition networks tells us that those

networks are really important for dads

to use when they become parents and

they're getting a lot of practice

putting those networks into into use.

>> I thought you said that section of the

brain shrunk.

>> Yes. Because the brain is becoming more

efficient. So, it's losing all the extra

pathways and you're sort of building a

super highway for that specific social

information.

>> Sounds a bit counterintuitive because I

imagined that my brain would grow when I

get better at something.

>> You would, but in this case, the brain

is actually shrinking. And I know it it

sort of feels like a puzzle to wrap your

head around, but it actually does

reflect that the brain is working

better. And is there a relationship

between how hands-on the father is and

the amount of shrinkage that happens in

their brain?

>> Yeah. And my lab found that

relationship. So when dads told us

before birth that they felt more bonded

to their unborn baby, when they wanted

to take more time off after work, and

when they told us 3 months after birth

that they enjoyed their babies more,

they felt more connected and bonded to

them, and they were spending more time

taking care of their babies, they had

more profound brain shrinkage. All of

this seems to support the contention

that the shrinkage is really adaptive

and it's enabling men's adjustment to

parenthood.

>> Is there any other biological changes

that take place when someone becomes a

father?

>> So, we also see changes to men's

hormones.

>> I talk about this in the book. Men

typically show a drop in testosterone

>> and I've got a big thing here.

>> Yeah, let's talk about testosterone. So

typically men when their hands on as

fathers show about a 25% drop in

testosterone and some of the best

studies of this have been done

longitudinally in the Philippines.

Before we had longitudinal studies

people said well maybe lower

testosterone men are just choosing to

become fathers. And so looking across

time lets us tease that out and see is

there something about fatherhood that's

actually changing testosterone. And so

when you look across decades, you find

that testosterone is typically pretty

high before pregnancy happens. And it's

adapted to have high testosterone. You

know, testosterone's been studied a lot

in birds. It's also been studied in

rodents and in other mammals. You want

high testosterone at the start of

breeding season when it's time to

maximize your chances of producing

offspring. You want to compete. You want

to build status. You want to fight off

your rivals, high testosterone is your

friend. Once you've accomplished your

reproductive goal and you've caused a

pregnancy and you want your offspring to

survive, you want to be investing and

nurturing that new baby. And this is

what we saw in the men in the

Philippines that as they were spending

more time taking care of kids, they

showed a sharper drop. And and then you

typically see some rebound when the baby

is getting older. And again, this is not

unique to humans. We see it all over the

animal kingdom.

>> So during a pregnancy, something some

chemical tells my body

>> Yeah.

>> that I need to make less testosterone

even though the baby's not here yet.

>> Yeah. It might just be your proximity to

your pregnant partner.

>> Interesting.

>> Yeah. Our lab found expectant dads and

expectant moms had correlated levels of

testosterone during pregnancy. And the

more strong that relationship was, the

more dad showed a drop in testosterone

after birth. But I want to caveat cuz I

think a lot of men are really concerned

about the idea that testosterone might

drop. And I think we have a really

strong narrative right now that

testosterone sort of like equals

successful masculinity.

>> And masculinity is not about a

particular hormone. It is about a body

that is responsive to our goals and that

sets us up to meet the demands of our

environment. And so having a biology

that fluctuates across the lifespan as

our reproductive strategy shifts is

really adaptive. We want to be flexible

and that doesn't always mean maxed out

testosterone. So high levels of

testosterone actually decrease our sperm

count and they are bad for our immune

system.

>> I think some men might be concerned that

dropping testosterone might make them

worse in the gym or it might make them

less ambitious or less able to pursue

their goals in life. Is there any truth

to that? There's definitely a link

between testosterone and men's,

you know, muscle mass and their

motivation, their drives, but these are

not onetoone relationships. So the human

hormone literature is messy and a lot of

these are weak correlations. So

testosterone doesn't necessarily equal

success at work, for example. And high

testosterone can get in men's way in in

multiple ways. So there are links

between men's testosterone levels and um

relationship satisfaction in the couple

relationship. So my lab did a study

where we found that men who had

relatively higher testosterone after

their baby's birth had uh partners who

were more dissatisfied in the

relationship and reported more intimate

partner aggression. So the dads

themselves reported more parenting

stress. So there's a little bit of a

mixed bag of high testosterone and what

it looks like. you want is to hit a

sweet spot. You don't want testosterone

levels that totally crash. My lab has

also found that when testosterone is

really low after a birth, men have

higher postpartum depression symptoms.

You don't necessarily want testosterone

levels that are skyhigh either because

that can cause problems in your intimate

relationship and it can make it hard for

you to switch into nurturing and

parenting mode. So, the men who seem

most successful in our study were men

who had mid-range testosterone levels.

that could be flexible and that could

adapt to different life changes.

>> And am I right in thinking that the more

time you spend hands-on as a father in

those studies that they did on men, the

lower your testosterone will go?

>> Yeah. So the longitudinal work in the

Philippines found that when men spent

more time changing babies, doing

hands-on care, sharing a sleeping

surface with babies, they had more of a

testosterone drop. So the testosterone,

the hormones are responsive to the

context and to what we're doing. But

testosterone does rebound, you know,

after birth. So, it's not necessarily

the case that testosterone is going to

bottom out and it's going to stay low

forever.

>> You know, you said a second ago that men

that had crashes to their testosterone

during the pregnancy and thereafter um

had a high likelihood of experiencing

postpartum depression themselves.

>> Does that are you implying that that

means that there's an ideal amount of

time and hands-onness that a father can

spend with their child to make sure

their testosterone hits that mid-range

point?

>> Yeah, it's it's a really good question.

I mean, I don't know that we know for

sure if there's like a dose of parenting

involvement that sort of lends itself to

an ideal amount of testosterone. It's

hard to optimize your way out of these

natural changes. I I don't want to

discourage dads from being hands-on with

their kids because they're worried

they're going to pay some kind of

physiological tax. I think it's more

like make sure you're protecting your

sleep, which we know is linked with

overall health. Make sure you're getting

time to exercise and to socialize, you

know, to participate in activities that

bring you joy. Like, those are ways to

help mitigate your risk that I think

will be more successful than trying to

hit a particular hormone level.

>> My brother is a year older than me and

he has um three young kids under the age

of seven

>> now. Um they were actually just here.

They just left. But um I noticed a

remarkable difference in him when he

when his wife Julia got pregnant.

>> What did you notice?

>> Just a a total shift in what he wanted

out of life.

>> Yeah.

>> And so before growing up, I remember um

one day seeing him on the computer

figuring out which job would pay the

most money. And he was very very smart.

He he is very very smart.

>> And he picked he sort of orientated his

career towards the job that would make

the most money.

>> And then he was successful. He went to

LSSE, got the job. Um, and then shortly

after graduating university, met

someone, they got pregnant unexpectedly.

>> And I watched my brother go from someone

who was like really striving for

material goals.

>> Yeah.

>> To someone who suddenly placed the

material goal immediately after. How do

I retire and spend the maximum amount of

my time with my kids?

>> Yeah.

>> His kids are number one above all

anything else. And it's something I

admire a lot about him. But the most

remarkable thing as someone that's not

gone through that transition cuz I've

not had kids yet is just watching how

profound the change was in him in terms

of his stated goals and ambitions.

>> Yeah.

>> Like what is this?

>> I'm so glad you said that cuz that's

something I heard from so many of the

fathers that I interviewed for the book

is that you experience this profound

shift in your values and your

priorities. And a lot of men, you know,

if you survey parents, you say, "What

are the most meaningful priorities in

your life?"

Men are just as likely as women to say

my kids.

>> And I think fathers increasingly are

recognizing that the parenting role is

really central to their self-concept.

And you know, like we're in a culture

where I think it can be hard for men to

find a sense of meaning and purpose and

connection to other people. Being a

parent can can give you that sense of

meaning and purpose. M and so, you know,

I think that's a really important

framing around, you know, your

testosterone level might change or your

brain might shrink, like things that

maybe sound a little scary and negative,

but they're in the service of this

larger goal, which is building a more

meaningful life. And I think, you know,

like a message to men and also to women,

to moms and to dads, is anything that's

worth doing is hard. Being a parent is

really hard. You know, you are

sacrificing yourself. You're losing your

sleep. You are getting extra wrinkles.

Ask me how I know. But you are

benefiting from this sense of connection

and purpose that you know it sounds like

your brother has been totally

transformed by. And I think we're in a

lot of ways like selling young men on

this message that you should be

optimizing your bank account and your

body fat percentage and you should be

out there hustling as much as possible.

And I think that can be a little bit of

a hollow message because what we keep

learning again and again from the

longevity studies is that the quality of

men's relationships is the best

predictor of their well-being and old

age. So men with healthy marriages, men

who have positive relationships with

their kids, those are the men who age

well, not necessarily the men who've

maxed out on, you know, riches or the

perfect body fat score. It is is it's

really a remarkable thing because when

you as you look forward into becoming a

parent, you often see the sacrifices

you'll have to make. You hear about,

okay, you're not going to sleep as much

as you used to. You'll hear about um the

anxieties of being a parent and loving

something so much more than yourself and

all these things. But that sort of

profound psychological, biological,

hormonal shift,

>> you kind of just have to believe in it.

>> Yeah. Yeah,

>> people like tell you about it as if it's

like a almost like a like almost like a

religion. I say that because you have to

have faith that the profound upside will

be um worth the very obvious cost that

you see parents, you know, the

sacrifices they have to make.

>> Yeah, I think that's exactly right cuz I

think a lot of the downsides are really

visible. Yeah.

>> Like we've all been on a plane with a

crying kid and we've seen the frantic

parent trying to calm them down.

>> We've all seen a tantrum in the grocery

store, right? Like that that stuff is

right in your face. But the upsides are

sort of invisible. You know, just like

the joy of seeing your child's face as

they discover something new

>> or, you know, getting to snuggle late at

night and feeling this sense of

closeness that you've never had, right?

That like love that's bigger than

yourself. Mhm.

>> And I think it's important to speak

about the benefits as well as the

downsides because we humans crave

connection and you know we crave care

and I think becoming a parent is an

opportunity to provide care on a scale

that's hard to find in other ways.

>> I also want to hear from you about how

the mother's brain changes through

pregnancy and beyond. Yeah. cuz Julia,

so my brother's wife, she was here as

well and she's remarkably different now

that she's had these three beautiful

children.

>> And I was asking her last night cuz she

was in the sort of corporate world

before. I was saying, you know, on when

they grow up and they leave home, which

again is probably the worst thing you

could probably say to a mother who has

three young beautiful children and who's

already like anxious that someday

they're going to

>> fly the nest. I was like, what what what

will then be in the place of these three

kids in your life? Would you want to go

back to like the corporate world or do

you want to do something else? and how

has it reordered your sense of meaning?

But tell me, how does the mother's brain

change?

>> Yeah, the mother's brain changes really

profoundly as well. Moms are losing

about 2 and 12% of their brain volume

from before pregnancy to after birth.

Dads in our studies, we found they lose

about 1% of their brain volume. So,

similar pattern in similar parts of the

brain, but the magnitude is different

and there's more variability in the

dads.

>> And how did you conduct these studies?

What was the methodology? So, we

recruited a bunch of firsttime parents.

These were uh all couples that we

recruited during pregnancy.

>> Our only rule was that you had to be

cohabiting and you had to be planning to

continue cohabiting after the birth

because we really wanted to capture the

dads and get their experience, you know,

being in proximity to their babies. And

so, we brought them into the lab. We

asked them every question we could think

of. We sampled their blood, their

saliva, their hair. Uh we had them fight

with each other on camera. We scanned

the men's brains and then about 6 months

after their baby was born, we brought

them back into the lab, blood, saliva,

hair. This time we got a breast milk

sample. We got a sample of baby poop and

we had them fight again and we scan the

dad's brains again.

>> You had them fight again.

>> We had them fight again. We wanted to

see how do couples communicate with each

other and does that change across the

transition to parenthood and also what

communication styles are going to

predict better couple level adaptation

to becoming parents.

>> How did you get them to fight? I need to

make sure I don't do that.

>> So we gave them a whole list of

different topics. We said these are

topics that couples commonly argue about

which are hot button issues for you and

your partner. And so we had both the mom

and the dad fill these out

independently. And then we went through

and we saw what are the issues that both

people are endorsing and we said we want

you to talk about this issue. Don't hold

back. We're going to give you 15 minutes

sit in this room and we, you know, watch

them talk through it. They weren't, you

know, like punching each other, but the

conversations were often contentious

because they were talking about issues

that were frequently objects of

conflict.

>> Mhm. Okay. And what did you discover?

>> So, we discovered that when couples

fought more negatively with each other,

they subsequently reported more

difficult birth experiences.

And it's interesting because birth is a

time in which moms need a lot of support

and the partner is often a primary

person who's in the room providing that

support. So, when couples have, you

know, sort of like a like a toxic

difficult relationship, that can really

color mom's experience of the birth.

Are you saying that because the person

that they fought with and don't have a

good conflict resolution strategy with

it was in the room, they had a bad birth

experience or did something actually

happen in the birth experience? Did like

the the husband make a comment like

>> Yeah. No, I mean we didn't record their

conversations during the birth, but we

actually did get the charts from the

hospital or the birth center after the

baby delivered and we looked at

complications. We looked at how

medically complex the birth was. And we

found that when couples fought more

negatively and less positively during

pregnancy,

>> during pregnancy

>> during pregnancy, so you know, they're

about 6 months into pregnancy. A few

months later, when it's time to deliver

the infant, they had more medically

complex births. And they also appraised

the births as more stressful. So the

conclusion is it's thinking about the

couple relationship is actually

important when we think about birth.

There's been a huge sea change about how

we deliver babies. You know, like it

used to be that men were never in the

birthing room. So, babies were t

typically delivered with the assistance

of a female midwife and female

relatives. And it really wasn't until

birth moved into hospitals in, you know,

the late 19th century, suddenly you had

a male physician who's presiding over

the birth. And then really it wasn't

until the 60s and 70s that dads started

to advocate for their inclusion in the

birth room. They said, you know, we

don't want to miss this. We want to be

present. But because historically dads

have really not been part of the birth

experience, we haven't necessarily

thought about the couple relationship as

a place to intervene. If we want to make

birth go smoothly, we actually want to

be thinking about dad's mental health

and we want to be thinking about coup's

relationship functioning because those

things might actually affect mom's

psychological experience at birth.

>> So you're saying don't fight during

pregnancy.

>> Yeah. Well, or just find more effective

ways to fight. You want to figure out

ways to

calm each other down, validate each

other, not necessarily, you know, amp

each other up and get into these really

negative spirals. I guess I want to push

on a point of nuance here because I'm

concerned that

>> expectant parents might be looking at

each other right now as they listen to

this episode. I imagine we've got a lot

of expectant parents listening and

they're thinking, "Fuck, we had a fight

last week and we got the birth coming up

in a couple of months."

>> Yeah, there's nothing wrong with

fighting. In fact, I'm a big believer

that it's good to air out your concerns

and grievances. What we were looking at

specifically were negative conflict

behaviors.

>> Okay? things like criticizing, showing

contempt,

um stonewalling, so like refusing to

listen to see the other person's

perspective. Actually, one of my really

smart grad students is working on a

project right now where he looks he's

looking at like what is kind of like a

magic ingredient that helps couples

shift from being negative with each

other to being positive with each other

during these conflict tasks. He's like

literally looking at the same task and

he's finding the ingredient is

validation. So just conveying to your

partner, I understand what you're

saying. I see where you're coming from.

I'm right here with you. I get it. Like

those kinds of behaviors make a huge

difference because they sort of take

like a lot of the tension and

frustration out of the conversation. As

soon as you feel really heard by your

partner, you you know the wind is a

little bit out of your sails for being

furious.

>> I sometimes worry that a lot of people

are waiting for perfection

>> before they step into the next season of

parenthood. Maybe I'm guilty of this

myself a little bit to some degree. I

think me and my partner talk about this

sometimes, me and my fiance about like

it doesn't feel like there's ever going

to be a perfect time to have kids.

>> Yeah. when you look at the nature of my

life and her life, you go, "Look, crazy

crazy schedules. Um, there really is no

time right now." Um, but I reflect and

go, "Well, everything that I do now,

including this podcast, at the time that

I did the first episode, there was no

time, but I made the time."

>> Um, and I sometimes worry that as as

young people, we are in a culture that

is waiting for um more perfection than

than is coming in terms of our romantic

partner or our circumstances. And of

course there is a a fundamental sort of

basis of security that everybody needs

to be able to bring um a life into the

world and often people don't have that.

>> Yeah.

>> Um but I'm wondering what your thoughts

are on that.

>> Yeah. I mean I had this conversation

with my grad school adviser. I said I

would love to have kids. What do you

recommend? When is the right time? And

she laughed and she said there is no

right time. You just have to do it. You

just have to make it work because once

the baby shows up, you'll figure it out.

And that was tremendously good advice

and and you know led me to start having

kids within the next few years after

that conversation.

>> Really?

>> Yeah. Yeah. I was like, "Okay, I guess

it's I'm just going to go for it. I'm

going to make it work." And it was hard,

>> but we did in fact figure it out. And I

think, you know, when you optimize

everything and you feel like you need

the perfect conditions, I need to own a

house. It has to be this many bedrooms.

I need, you know, this level of

stability. Yes. All those things are

terrific, but historically, you know,

people had kids young and you know,

often they found that having kids gave

them a really strong impetus to get

those things together. We used to think

about having kids as like a cornerstone

of a life. It's like a foundation. You

know, you do that and then you sort of

build your career and everything else.

Now we kind of think of it as like a

capstone. It's like your crowning

achievement. you've got everything

perfectly set and now it's time to have

kids. And I think the problem with that

is first of all, our biology doesn't

always agree. You know, we can sort of

lose our our best window in which to

have kids. And I also think like having

kids isn't just an individual

responsibility. We need to be thinking

about it as it's a collective

responsibility. It's societal. We are an

alo parenting species. So what that

means, we're we're cooperative breeders.

We raise our kids in community. That's

how we evolved. That's if you look at

hunter gatherers, that's how they raised

their kids. We are not designed to do

this in isolation. And and I think, you

know, when you think about like what

does a healthy society provide for

parents to reduce stress, right? Like

generous maternity and paternity leaves,

you know, job protections, child care.

Like I'm a big believer in having strong

policies that make it easier to have

kids

>> because I think in the absence of those

policies you feel like it's your job to

get everything completely lined up and

that time might never come especially

not in a you know tempestuous economy

>> and I think we're seeing some of the

symptoms of exactly what you've

described there. A landmark 2024 study

published in the Lancet projects that by

the year 20100,

97%

of all countries and territories will

have fertility rates too low to sustain

their populations. The global fertility

rate has plummeted from an average of

five children per woman in 1950 to just

2.2 today. According to the CDC and Pew

Research data, the US total fertility

rate just hit an all-time recorded low

of 1.6. This is far below the

replacement rate of 2.1 children per

couple, I guess.

>> Yeah.

>> Required to keep the population stable

without immigration. CDC data shows

total US birth rates dropped yet again

by 1% in 2025, falling to roughly 3.6

million babies, continuing a nearly two

decade downfall slide since the Great

Recession. And lastly, because the

fertility rate is crashing in

high-income nations, but remaining

comparatively high in specific lowincome

regions, it is predicted a massive shift

in human demographics will take place.

And by 201, 100, one in every two

children born on the planet will be born

in subsaharan Africa.

>> It's all quite um all quite shocking to

hear, isn't it? I think

>> Well, I mean,

>> inconceivable. I thought we'd growing up

everyone was talking about uh too too

many people being on the planet,

>> right? There was this narrative of the

population bomb which was this really

popular theory in the '60s that we had

too many children.

>> Yeah.

>> And we needed to, you know, adopt

contraception and we needed to prevent

too many children from being born. We

all took that too literally and maybe

overcorrected cuz now you have this

population drop. And it's concerning

because what you don't want is a society

with what's called an inverse age curve

which means that you have many more old

people than young people

>> because you know then you don't have

enough caregivers for the older people.

You don't have enough people to sustain

the economy.

>> You don't have innovators. You don't

have you know the folks who are sort of

building your future. You've depopulated

that and you have a very aging

population and that can create a lot of

instability.

So I I think we need to be thinking

about, you know, how do we make

parenting easier and more

[clears throat] desirable for young

people because I think that we've

managed to market it as an [laughter]

undesirable choice.

>> How does how do we make it easier and

more desirable for young people?

>> So I think part of it is the

conversation we're having right now

where we're talking about the meaning,

the purpose, the benefits that you can

get from your relationships with others.

I think that we need a cultural reframe

around care to raise the value of care.

One of the reasons I'm interested in

fatherhood is because I think seeing men

as talented caregivers kind of unlocks

this appreciation we have for the

importance of care.

>> The shift you described your brother

undergoing where he went from

transactional, how can I make the most

money to my kids matter, how can I spend

the most time with them?

>> Yeah. I think is a is a really valuable

shift in purpose that you know at scale

would make societies healthier and more

empathetic.

>> So there's like two things I think are

worth saying here from my perspective.

The first is I think it's important that

we express the fact that a not everybody

can have kids because of you know

reasons beyond their control. I think

the second thing is not everybody wants

or should should want to have kids you

know depending on their circumstance.

Um, and the third thing is that I do

feel in my personal circumstances, um,

when I think about what I want from my

life, again, this is about me, I do feel

tremendously positively jealous of his

life.

>> And that's it's a strange thing because,

you know, he has a couple more gray

hairs than me, even though he's only a

year older. So, you know, everything in

life is a trade-off. But the like deep

sense of meaning and purpose that even I

experience when those kids are here like

they were at my house for the last

couple of weeks and it's it's everything

seems yeah incomparable in in terms of

like meaning to these beautiful

children.

>> Yeah. They're just endlessly curious and

fascinating

and you know there's very little you can

get from scrolling on a screen that you

know that to me is as fulfilling as what

you can get from watching a baby learn

something.

>> It used to be that working for yourself

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Am I right in thinking that parents have

different brains as it relates to

the brain being protected?

>> Yeah. So there's this really interesting

emerging body of research suggesting

that being a parent is neuroprotective

in late life. So there are studies, the

UK bioank is the biggest repository of

brain scans from people in their 50s and

60s and they find that both men and

women who report having had more kids

have markers of a younger looking brain

age. So if you do a machine learning

algorithm that adjusts for your

chronological age and then you know

takes what the scans looks like and uses

that to estimate what they think your

brain age is. You look relatively

younger when you report having had more

kids. It seems like the greatest benefit

is at two or three kids. After that it

kind of levels off. You don't

necessarily get a big benefit from

having had six kids compared to having

had two. But it suggests that there is

something about the practice that you

get to your social brain and to your

empathetic brain that is really

beneficial to your, you know, brain

plasticity and functioning later in

life.

>> That's quite surprising because you'd

think, you know, parents go through a

lot of stress having lots of kids. So

you you'd assume that they'd be sleeping

less. You'd assume that would be bad for

the brain. But you're telling me there's

evidence that it's actually protective

to be a parent of two or three kids.

>> Yeah. I think it's healthy to think

about the short-term cost and then the

long-term benefit.

>> Okay.

>> So, you know, like there are plenty of

studies that have found that moment to

moment, parents of young kids say that

they're less happy.

>> Mhm.

>> They're more tired, they're more

stressed, they have more going on. We've

talked about the, you know, brain

changes, hormone changes. But then, you

know, if you look longer in later life,

people will report more fulfillment. So,

it's like you're you're doing something

that's not very fun. It's taxing. It can

be very isolating and yet you're kind of

reaping this longer term benefit in

terms of the power of those

relationships and that sense of

connection with other people. That

social integration and that practice

trying to understand others that is

really beneficial like it's a glue for

creating good relationships.

>> What is it exactly about being a parent

though that's going to make my brain

more protected when I get older? You

know, one of the theories I had was that

because, you know, when those three kids

were here, they had me playing all kinds

of bloody games. They wanted to play

hide-and-seek for seven hours. And it is

somewhat, you know, actually picking

them up all the bloody time cuz there's

three of them. And one of them's eight.

I can't really pick her up easily. The

other two I can get them up and then she

starts complaining that I've not picked

her up. So, I have to pick her up and

I'm like, "Wow, what a workout."

>> It is both a cognitive and a physical

workout [laughter]

>> when they're around.

>> Yeah. Is it that like I'm building up

brain reserve because they're

challenging me and having tantrums and

they're wanting to play and they're

engaging me all the time? Is that why

it's protective?

>> I think it's like sudoko for your social

cognition, right? It's like you're doing

crossword puzzles but instead of like,

you know, the sort of practice that

you're getting for putting words

together, you're getting practice

understanding people's minds and

intentions and communicating and

responding to them and being sensitive

to them. And all of that is putting you

through a workout and it's also a full

body workout because kids are really

embodied.

>> And there's [clears throat] actually

interesting research that dads

especially play in these physically

demanding kind of vigorous ways with

>> Exactly. it was my job. My job was to

pick them up and throw them as high as I

possibly can.

>> Yeah. And kids love that.

>> Yeah. And then me now. And then like I

threw that and then it's like me now.

And then I just I was like I'm going to

lose weeks throwing these kids in the

air. But also I'm going to break

something.

>> Yeah. I mean, I think my husband never

had to see the chiropractor until, you

know, he became a dad and all of a

sudden you're throwing them up in the

air all the time. But that kind of play

is really good for kids because it's

testing their limits. It's challenging

them and it's actually helping them

build their risk tolerance. So like

think about like the the moment of fear

that you have when you're thrown up in

the air and then the relief when you're

caught. like

>> you're basically practicing your emotion

regulation skills on a small scale so

that when you're thrown into a scary

situation at school, you have a stronger

sense of confidence.

>> My other theory around why having

children would be neuroprotective for

the brain was around oxytocin.

>> And I say that cuz I sat with Robert

Waldinger who's done that sort of that

long Harvard study on human happiness.

And the conclusion is that one of the

single biggest predictors of longevity

is whether you have strong

relationships. And again, I I had

another scientist say to me that

oxytocin, the bonding chemical, is

neuroprotective.

>> So I imagine having three children is

going to equal a lot of oxytocin, which

is going to equal some

neuroprotectiveness.

>> I mean, we are social animals. We are

designed to bond with each other. We

pair bond. We bond with our kids. That's

really healthy. I love Waldinger

studies. I cite those in the book when I

talk about, you know, if you really want

to think about what creates longevity

and well-being late in life, look at

your relationships. And, you know, I

feel like he shows that really well with

this 80year study that he's been doing.

There are all these like brain changes

and hormone changes that are designed to

facilitate to help us build those bonds.

And that's a lot of what is sort of

going off in early parenthood is like we

are sort of reorganizing to become more

sensitive, more attentive caregivers.

It's not like, you know, some people are

just destined to be great parents and

some people aren't. It's like as we put

in the experience, as we get the

practice, we put in the reps, we're

building that brain and body that helps

make us really great sensitive

caregivers. And then that I think can

can transfer over to our other

relationships, too. If you've learned

how to calm a kid down from a tantrum,

you are probably going to be a very

effective manager at work. If you have,

you know, negotiate with three kids who

all want to pick you up at different

times, you know, you're probably going

to be a better problem solver in your

couple relationship. Like, those are

just skills that you're building that

can cross domains.

>> I was just looking at some of the the

research on this and it says that

research shows that oxytocin actively

downregulates harmful pro-inflammatory

cytoines in the brain. It acts as it

acts on the brain's immune cells um

making toxic inflammatory responses

lower. And studies on aging mice

demonstrated that long-term oxytocin

treatment concurrently enhanced the

brain's plasticity which directly

improved learning and made them better

with memory as they aged. And in terms

of Alzheimer's, in animal models of

Alzheimer's, oxytocin has been shown to

reduce the toxicity of amalloid beta

plaques, the toxic protein clumps that

are the hallmark of Alzheimer's disease,

which is fascinating. And that's um

that's the chemical that is produced

from bonding.

>> Yeah, that's a pair bonding chemical.

It's it's an affiliative neuropeptide.

So, it sort of helps us shore up our

social bonds.

>> Touch is really important, isn't it?

Yeah.

>> You know, it's such an important thing.

>> Yeah. My lab found actually that when

dads engage in more physical touch that

there's a type of touch that's called

proprioceptive touch which is exactly

what you were just describing like

picking babies up moving them around

playing with them like in space. It's

that sort of like vigorous touch that we

often associate with fathers.

>> When dads did more of that they

subsequently had higher oxytocin levels

when we did a blood draw in our lab and

that's been found in some other labs as

well.

>> Do you know Erica Commissar he's been on

my show?

>> I do. One of the things she says which

has been a little bit controversial is

that she's argued that placing children

under the age of three in daycare causes

profound separation trauma and elevates

cortisol to dangerous levels. So she's

quite against daycare.

>> I so I politely disagree. I both my kids

went to daycare where they thrived and I

am a big believer in this idea of alo

parenting which is this idea that we

collectively raise kids. We are designed

to help each other out and share care.

>> [clears throat]

>> And so the model of single parent,

single child, isolated in a suburban

home is a very weird model in the

context of human history. And so I think

this idea that, you know, we can't

participate in shared care or that kids

can't do well in group care settings to

me is a little exaggerated. I do think

it's very true that it's about timing

and when is the right window to, you

know, put kids in group care settings.

it it's you know ideally when kids can

benefit from some social interaction

which is usually a little older in

toddlerhood. So you know 18 months and

beyond. Very young babies often do

better when they have a single

caregiver. They have a more stable

attachment figure that they can bond

with. But babies can form really strong

attachments with their dads with a

caregiver. It doesn't necessarily have

to be the case that mom is the only

person that needs to be present for

every moment of an infant's life because

I think that model is not terribly

sustainable for parents and parenting

stress is really bad for kids. You know,

and this goes back to the birth rate

conversation. I think we need to be

thinking about parenting in ways that

are sustainable that allow us to get

help. And we also, you know, if we

really think that we don't want kids in

a lot of early child care, we need to

support that with universal paid

parental leave, which is not available

for most parents in the United States.

So, a lot of moms are coming up against

a reality that doesn't fit with what

some of the parenting gurus are telling

them is the only way to raise their

kids. And I think that creates a lot of

anxiety. If you think about the early

phases of a child coming into the world

like year one, year two, year three, is

there any differences in when either

parent plays a different type of role?

>> There's a little bit of difference and

it sort of depends on, you know, what

the parent styles are and what the kid's

situation is. But there's a chapter in

my book where I talked with Richard

Reeves, who's done a lot of great work

on masculinity and manhood. And he says

he thinks dad should be able to get

paternity leave up to their kid's 18th

birthday because a lot of the time dads

find that their sort of best

relationship with their kid happens

later in childhood, even in adolescence.

You know, he talked about taking his

kids on trips, teaching his sons how to

drive. And so I think like dads can kind

of come in at different points along a

kid's development and provide a lot of

value. I think early in infancy if mom

is breastfeeding it's important for the

baby to get that sort of regular access

to milk. Um, you know, of course moms

can pump, dads can do feeding, but it is

often a source of challenge for couples

when a baby's first born and dads feel

like mom has a really big biological

head start. You know, she has had the

pregnancy, she's been able to build a

bond with the child. Breastfeeding is

like this magical formula that she can

give the baby to um help soothe. And so

I think a lot of dads struggle to find

their place in early parenthood in the

first year or two because they're like

what am I supposed to do? I you know it

takes a little while for dads to kind of

come online

>> as parents. You know dads need I think

some space and opportunity to figure

things out and you often get into this

dynamic where mom is kind of the default

parent in the early years and dads are

waiting for their instructions. when

you've gone out on the book train,

you've spoken to both fathers and

mothers. What is the like central point

of contention that you discover?

>> It's funny. I was just at a friend's

book club meeting and it was a mix of

couples. It was moms and dads. And the

thing that they all got into was this

concept of maternal gatekeeping and sort

of male malingering, which is this like

double-edged kind of. And so maternal

gatekeeping, it's a somewhat

controversial term, but it just refers

to anytime a mom consciously or

unconsciously sort of puts up a

roadblock to dad's fully participating

in parenting. And it could be as simple

as the baby's fussy and crying and mom

says, "Hand him to me. You know, I know

what to do." But over time, that kind of

kind of spiral into a pattern of mom

becomes the authority figure. dad is

seen as like the bumbling hapless kind

of appendage and and dads ultimately

feel like their contributions aren't

valued or you know mom doesn't really

want them to have a lot of independent

time maybe it's cuz mom doesn't trust

the dad right which is an area where I

think having communication and making

sure there's trust before the birth is

really important but you know the flip

side of maternal gatekeeping is what's

called weaponized incompetence or

husbandly mlingering

which is when you know dad who's a

totally competent let's say project

manager at work who can handle lots of

different spreadsheets and a whole

workflow suddenly doesn't know what to

put in the diaper bag or you know when

when we were at the book club meeting

one of the moms was saying their baby

was a couple days old there was a giant

diaper blowout and she had gone out for

a 10-minute walk and her husband called

to be like what do I do she's like I've

been a parent for exactly 2 days that's

exactly as long as you I No idea. You

got to figure it out. He's like, "But

the poop's on the wall." She's like,

"I'm sorry. You You can use the wipes."

You know, that same husband, she told me

later, was in charge of packing lunches.

And a certain point, he said, "Do you

give the kids anything but chicken

nuggets?" She said, "Well, there's

fruit. You can cut up some avocado, you

know, like throw stuff in." So, I think

that is sort of like when dads act like

they just have no idea and it's mom's

job to solve the problem. Mhm.

>> And so I think a lot of moms are sort of

frustrated with what they see as that

dynamic happening. At the same time,

I've talked to a lot of dads who said,

"I would love to have done more, but my

wife insisted on organizing everything,

scheduling everything, telling me what

to do. I never felt like I got an

opportunity to fully step up." So, I

think that's an area where couples

really need to iron some of this out

even before the baby comes. Mhm.

>> Who's going to do what and how are we

going to balance it in a way that we

both get some ownership, we both have

some opportunity and we can trust each

other.

>> Talking about that parents often report

is that post pregnancy there is a change

in their relationship and intimacy. Have

you done any studies on that?

>> Yes. And that is one of the most robust

findings in transition to parenthood

research is that there is a drop in

couple relationship satisfaction often

around the birth of a new baby. And it's

not surprising. You take two people who

are having fun together, you sleepd

deprive them, you give them a lot of

extra responsibility, and then a baby

who's crying and demanding that you know

they get out of bed at multiple times

during the night. So, you often get a

lot of conflict around who's going to do

what. Um, you know, who's more connected

to the baby and and you know, I think

it's one of those things where

forewarned is fore armed. If couples

know that this is going to be a risky

time for their relationship, they can do

more to shore up their communication

before a baby's born.

>> Have you ever quantified how different

the relationship is on the other side of

giving birth? We have definitely given

lots of different couple relationship

questionnaires and we've measured them

and we've looked at that dip and we've

seen that there is in fact a

statistically significant drop in

relationship quality

>> and sex life.

>> And sex life. Yeah. I mean because of

course, right? Like you've got an extra

person in your bed a lot of the time or

near your bed.

>> And if you have delivered the baby

vaginally, there's also a lot of stuff

that's sore and might need to get

stitched up and even more so if it was a

C-section birth.

>> And does that at some point go back to

pre-birth levels in terms of

relationship satisfaction?

>> Yeah. So there is a lot of variability

in couples relationship trajectories. So

there are some couples for whom

relationship quality continues to dip

and often the relationship dissolves.

There are also couples who report they

have a better quality relationship after

having parented together. You know

there's a richer relationship like I

feel that with my husband like I

appreciate him so much because I've seen

him negotiate with terrorists in the

form of our young children. So, you

know, I think like how well couples fare

is going to diverge sort of depending on

how well they can kind of muscle through

some of those early years.

>> Earlier on, you said that men experience

postpartum depression

um after the birth of their child

sometimes. And that's quite a

unconventional thing to hear.

>> When we think about postpartum

depression, typically it's in the

context of what the woman is

experiencing. Yeah.

>> Um, so it's quite interesting to hear

that that is a big issue for men as

well.

>> So technically postpartum depression

just means depression that occurs after

the birth of a baby. That's what

postpartum means. So that term

postpartum doesn't necessarily mean that

you know it's the person that's

delivered the baby. It just means this

is the time period after birth. And

there's some evidence that dad's

prevalence rate for depression, so in

new dads, it's about twice that of the

general population. So if you look at

non-fathering men, they have about half

the risk of depression as new dads. So

there's a big uptick in depression risk.

That doesn't mean that every new dad is

depressed. And new dads have lower

depression rates than new moms, just to

be clear. But it's also not a

competition. It's not a zero- sum game.

And I think there can be a lot of

constrnation understandably from moms

who feel like we have fought for the

term postpartum depression to be widely

recognized by the medical community.

We've advocated for this. Now that we've

succeeded, men are sort of trying to

take it over. And I'm sympathetic to

that argument. And a lot of moms have

said, "Why don't we call it paranatal

depression?" Fine. I think that's

totally okay. Parinatal just means

around the birth of a baby. And that's

legitimate, too. But if you think about

what are the risk factors for

depression, either in moms or in dads,

like in, you know, the period following

a baby's birth, it's a combination of

factors. It's multi-etermined, it's

hormone changes, it's sleep changes,

it's identity changes, it's relationship

changes, like relationship conflict,

changes to, you know, how you show up at

work, to your extended family. it can

reawaken childhood traumas that were

unresolved about how you yourself were

parented. So all of those things are

coming to the four and you're

preoccupied by what can be very

isolating and repetitive care for a

young baby and it creates kind of a

perfect storm of mental health risk.

>> You've um you've you've studied cortisol

changes um in couples, right?

>> Yeah.

>> And how they and how their their

cortisol interacts with each other. Is

there a biological divorce predictor in

terms of a specific way a couple's

cortisol syncs up or clashes in that

sort of first year of parenting that

tells you if their marriage is going to

fail before they realize it themselves?

>> Yeah. So, I have looked at cortisol

interconnection in my lab between

couples. So, how cortisol levels become

correlated over time. I found that when

couples had really strongly linked

levels of cortisol, they reported lower

marital satisfaction. And you'd think

like, okay, they've got more similar

hormones, that's probably a good thing.

We found the opposite in our lab. And I

think it's because you don't actually

want to be contagious to other people's

stress. When one person is really

stressed, it's helpful to have a partner

who can modulate that, who can calm you

down. So you don't necessarily want to

be exacerbating like amplifying the

stress state.

>> Interesting. This is fascinating.

>> There are some other labs that have

found that especially in a transition to

parenthood context, more synchrony in

cortisol can actually be a good thing if

you're looking from prenatal to

postpartum.

>> But outside of child birth.

>> Yes. So, this is interesting for me

because I was having a conversation with

someone the other day and she was

telling me that she emotionally is a

little bit more variant than her

partner.

>> Yeah.

>> And I was expressing a similar sentiment

saying that I think actually the reason

why my relationship works with my

fianceé Melanie is because

>> Mel is a little bit emotionally variant

and I'm kind of the like prefrontal

cortex sounding board

>> that kind of brings us back down. Yeah.

>> So her emotional variance is super

useful because she's almost like a

threat detector

>> in every regard. So if our relationship

is drifting a little bit or if we're

just she'll she'll know fast.

>> Whereas I take a little bit more time to

like to sort of have empathy to these

kinds of like shifts in our

relationship. She's like very in in

tune.

>> It's like a sixth sense she has.

>> Yeah.

>> However, sometimes that can mean some

things are harder to deal with

>> and maybe she's more prone to worry

sometimes. Mhm.

>> And I' I've often felt actually because

she's expressed this to me, she's

expressed the gratitude of me being able

to like bring her back to a place of

calm.

>> Yeah.

>> I've often felt that that's kind of like

my job.

>> Yeah.

>> And I've often thought that that our

relationship works because you do have

two different types of people.

>> Yeah.

>> And actually, this is not a plug, but

I'm an investor in a company called

Whoop.

>> And um on there they have the um stress

measure. Again, it's not a perfect

measure and nothing is a perfect

measure, but I was looking at our

differences in in the stress response

according to Whoop on the devices. Yeah.

>> And mine is very stable and hers is much

more unstable,

>> right?

>> But I I imagine that opposite's

attracted in this regard.

>> Yeah. I mean, it's interesting because

you could think if you were paired with

somebody who was super stable, life

might feel boring. If she was paired

with somebody who was really volatile,

life might feel too chaotic. So we

frequently are drawn to people who

compliment something about ourselves and

who are sort of different enough that it

can sort of expand our worldview. And I

I worked with a couple's therapist. This

is sort of his theory that it's often

the differences that drive us together

that can ultimately polarize us when

things go ary. So you can imagine a

future where she's always the emotional

one and you're always the calm one and

nobody gets a chance to break out of

that and that becomes really entrenched

in a way that like pulls you apart. But

you could also imagine a future where

you meet in the middle.

>> Yeah.

>> Like you become more emotionally

attuned.

>> Yeah.

>> And she becomes calmer and more stable.

>> Yeah.

>> And that's sort of the ideal, right?

That's what you want is you want to you

want to be joining around those

differences.

>> I would say that's definitely what's

happened.

>> Yeah. So that's good. So, it's a good

sign for your relationship.

>> Yeah.

>> Time to have a kid,

>> I think. So,

>> yeah,

>> I'm trying.

>> Good. [laughter]

>> We froze our embryos.

>> Excellent.

>> So, we've got them in the freezer.

>> Fantastic.

>> Which is an really interesting process.

I think this is probably worth spending

some time on because I think I was

living under the assumption that like in

my early 30s, I could just sort of

decide when to have a kid and I could

just, you know, have sex during that

little window they talk about where

she's ovulating and the kids would

appear. It's not necessarily how it

works. Yeah.

>> Turns out.

>> No, it's actually a little trickier.

It's trickier than I expected.

>> There's actually a chapter in the book

where I talk about paternity

uncertainty. One of the things that's

really unique and interesting about

humans is we conceal our ovulation.

So that makes us different from a lot of

other animals where when a female is

fertile, you know, because she changes

color, she starts dancing in a certain

way, she smells different, right? Like

there are all these really obvious cues

and as a result, males sort of know

exactly what window to jump in on. And

because we conceal our ovulation as

humans, it's always a little bit murky.

>> Why do we do that?

>> For one thing, it encourages pair

bonding because you can't just as a man

like just show up like the one day that

it's time to cause a pregnancy and then

take off.

>> So you have to court a woman, you have a

lot of you need a lot of repeated

opportunities. So if a man actually

wants to cause pregnancy, he's much

better off sticking with one woman and

really investing in that relationship

than he is like going out every night to

find a different lady. We form stable

monogous relationships because that's

actually adaptive for spreading our

genetic material and it also reduces

aggression. So there's one theory that

it reduces rivalry between women. If you

know that one of the ladies in your

group is fertile and you have it out for

her, you want to take her out during her

fertile period, right? So, concealing

ovulation actually reduces that rivalry,

that aggression.

>> Okay.

>> Um, it also makes everybody a little bit

more invested in babies because no man

knows exactly who's caused which

pregnancies. And as a result, everybody

has a little bit of an altruistic stake

in the future of our children.

>> Do you I'm not sure if this is an area

of research you've covered, but and

maybe I'm asking for a friend here.

>> Yeah.

>> Do you know what increases the

probability of conceiving a child? Cuz I

think about this a lot in terms of

stress and feeling comfortable and all

these kinds of things. Like I'm often

thinking about like don't argue with

her, keep her safe, make her feel really

secure.

>> Yeah. I mean, I think those are all good

instincts.

>> Is there research on this? There is

research on reducing stress for sure,

right? Like we know that stress makes it

harder to conceive. Of course, the last

thing you want to tell someone who's

struggling to conceive is reduce stress

because that's so invalidating because

you're like, I'm stressed about how hard

it is to conceive. Like don't, you know,

telling somebody be less stressed is

frequently not that helpful. But I think

your intuition is right that you

probably want to make the environment

calmer and safer. And you know, like you

can optimize nutrition. There's a lot

you can do, but there's also a lot that

is, you know, not up to you and

sometimes more intervention is needed.

>> What advice would you have for new

fathers?

>> This is kind of like one of the themes

of my book. Great fathers are made not

born. You might feel like you don't have

the qualities to become an amazing dad,

but it's really about your time, your

investment, the practice that you get,

and the extent that you care. That is

going to shape you. It's going to build

a brain and it's going to build a body

that will make you a tuned-in parent.

You know, give yourself grace. Like the

transition to parenthood can be really

challenging, but you can become an

expert in your own child and there is a

reward there. You will find enrichment.

You will find meaning. You will

rediscover your priorities in a way that

will ultimately bring a lot of value.

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>> Well, you've done so many studies.

>> Yeah, probably too many.

>> What is it? What are the studies that we

haven't talked about that are most uh

>> were most formative or surprising for

you?

>> We did a study where we looked at coup's

plans for how they wanted to divide up

baby care.

>> Yeah.

>> So, we gave them this questionnaire that

we called a who does what where they

were given 10 common baby care tasks

like changing diapers, feeding a bottle,

and they indicated on a slider how much

mom was going to do and how much dad was

going to do. And then we brought them

back into the lab about six months after

birth. We had them do the same scale.

And it was really interesting because

couples weren't actually great

predictors of how much dad was going to

do. So every single couple expected dad

would do more before birth than dad was

actually doing after birth. And there

are a lot of reasons for that. That

doesn't mean that anybody's a villain.

It just means maybe mom got more time

off from work. Maybe she was

breastfeeding and so the baby, you know,

she was she was with the baby more,

right? Like there are a lot of reasons

why that is the case, but we found that

when dads were doing more, they reported

that they were happier in their couple

relationship. But one thing we looked at

actually was how moms and dads talked

about how they wanted to divvy up baby

care. We measured how many times did

they say the pronoun we compared to when

you use the pronoun I where you're

talking about yourself. When you're

using we, you're talking about, you

know, you and your partner, the more

weness the dads were showing, the more

happy they were in their relationship

after birth. So, their investment, their

willingness to chip in, even if they

didn't totally realize all their plans,

was still linked with their