
How Men’s Bodies Change When They Become Fathers - cgoodmac
https://parenting.nytimes.com/health/fatherhood-mens-bodies
======
DoingIsLearning
Looking into the T drop in fatherhood, the original study seems to account for
self reports of 'sleep quality' but I wonder if sleep deprivation is not still
a confounder in this finding.

Annedoctally as a recent father of a 6 month old, I would likely self report a
good sleep quality in a questionnaire. However, objectively I know I sleep
about 5 hours 30min yesterday evening, which would be sufficient sleep
'deprivation' to impact T production.

Also I think parents in general will also have strong bias to not want to
acknowledge their own child as a 'nuissance' in a survey/questionnaire.

My key point is that it would be important to reproduce this finding with
actual sleep tracking instead of self-reporting sleep quality, to confirm if
this is indeed linked with a bonding/interaction mechanism with a child or an
unfortunate secondary effect of sleep deprivation.

~~~
reallydontask
> Annedoctally as a recent father of a 6 month old, I would likely self report
> a good sleep quality in a questionnaire. However, objectively I know I sleep
> about 5 hours 30min yesterday evening, which would be sufficient sleep
> 'deprivation' to impact T production.

When our 9 month old started to sleep through the night (at around 4-5
months), we'd get between 5-6 hours of sleep, which after the interrupted
sleep of the previous 4 months, felt like a full night's sleep but this is
sleep deprivation territory, specially given the fact that it was 7 days a
week.

I know I could only survive on this little sleep because I wasn't exercising.

> Also I think parents in general will also have strong bias to not want to
> acknowledge their own child as a 'nuissance' in a survey/questionnaire.

I think this is one of the biggest taboos in Western society:

Anything about a newborn/small child must be 100% positive

This is absolute bullshit

I can see the downsides of having a child without loving him (in my case) any
less

~~~
koolba
> When our 9 month old started to sleep through the night (at around 4-5
> months), we'd get between 5-6 hours of sleep, which after the interrupted
> sleep of the previous 4 months, felt like a full night's sleep but this is
> sleep deprivation territory, specially given the fact that it was 7 days a
> week.

Assuming you have the space for it, I never understood couples that insist on
both parents being woken up every night by a newborn. Much better for everyone
involved to trade off nightly so that the other person can get a full nights
rest.

I'm 99% certain that no baby cares that only one parent is being disturbed.

~~~
saganus
I'm not a parent so my knowledge here is pretty scarce, but what I've
understood from friends that have kids, is that when a baby wakes up, both
parents wake up due to instinct (i.e. is the baby ok?).

So I wonder if what you suggest would require some accomodation. E.g. have the
'on-call' parent sleep in the same room as the baby, and the other one can
sleep in another room with the door closed.

Is this what you mean by saying that both parent need not be waken up? or are
there some other methods that would help out with this?

~~~
koolba
> So I wonder if what you suggest would require some accomodation. E.g. have
> the 'on-call' parent sleep in the same room as the baby, and the other one
> can sleep in another room with the door closed.

> Is this what you mean by saying that both parent need not be waken up? or
> are there some other methods that would help out with this?

That's what I meant by " _Assuming you have the space for it..._ ". If the
baby is in a separate room and there's space for a bed or mattress, whoever is
"on-call" stays there and the other parent gets an uninterrupted nights sleep.
Or the reverse and the "resting" parent goes and sleeps on the couch. 7-8
hours uninterrupted on a couch wins over repeated interruptions on a bed.

Same system works if you have a grandma visiting to take over for a night.
There's no merit badge given out for everyone being equally sleep deprived.
It's just worse for everyone, including the baby.

If the mother is directly breast feeding then likely she's going to be taking
the heavier end of this load. If the baby is formula fed or she's pumping,
there's more leeway to switch off.

------
pricees
I was hoping this would explain my weight gain but I suppose I have to accept
that replacing daily workouts with 3 bowls of ice cream and magic shell may be
the culprit.

~~~
knolan
I’ve piled on the weight since our second was born. I attribute it to the
reasons mentioned here and also that I’ve not been cycling to work for the
last several months. We bought a new home and don’t currently have a place to
store my bike so it’s been languishing in my office. So I take the bus because
owning two cars is prohibitively expensive here in Europe. The bus is slower
than car and bike so I’m rushing out without breakfast and eating junk when I
get to work. On the bust home I’ll often snack on more junk.

All that changes today as we’re finally getting a garden shed and I’ll be back
in the saddle.

~~~
thisone
always interesting to see the differences in commute times per vehicle. Where
I am now, it's just over 7 miles to work, cycling is generally faster than the
bus, bus is much faster than car (bus lane for > 50% of the journey).

~~~
knolan
It’s been interesting as my commute changed from 7km to 18km to 22km in the
last year.

The 7km commute was a no brainer by bike. It took a leisurely 20 minutes where
as the car would be much the same with lots of tedious traffic. Bus wasn’t an
option on this route.

When I changed job my commute was 18km across the city. The car route involved
a toll on a congested motorway or through stop start city congestion. The bus
route required two buses with various degrees of waiting time made worse on
the way home because of the one specific bus I needed that always appears
unreliable. The car would take at least one hour bus would take up to two
hours and the bike about 50 minutes.

Now that we’ve moved home I’m even further away but there’s a direct express
bus that takes just 70 minutes. The car route is better, no toll and better
connected, but is still an hour in traffic and the bike is about an hour.

Cycling is great because you arrive to work energised, but it’s tough to do
everyday and still have energy for the kids at the weekend, so I’ll buy an
ebike and cheat.

~~~
thisone
lots of ebikes around nowadays. I only get annoyed at them when they pass me
going up the harder hills. And that's because I'm jealous of them, not
actually annoyed!

our bike club members assure me that an ebike isn't all easy sailing. I
believe them! With how heavy the ebikes can be, you can't just be sailing
along on the battery, not putting in any effort, and expect to go very far.

~~~
isodude
My parents use ebike to ride 30km with ease. It's a game changer.

------
tus88
> Women become pregnant before they become mothers. Men become pregnant
> _after_ they become fathers.

I heard this joke a while ago, and while cruel seems to have an element of
truth to it by observation. Lack of sleep, lack of exercise, less time to make
healthy meals seems to be a terrible combination for weight gain.

~~~
keymon-o
Good joke!

The experience itself is different. While for women it is more shocking and
exciting, men still need to handle their partner and other responsibilities
during this period and pretty much share that experience which, as article
suggests, alters them both in some ways.

~~~
senorjazz
> alters them both in some ways.

meh, not really. I don't think you can equate having to walk around
mother+baby type stores on your weekend with growing a baby inside you.

Life doesn't change "that" much for fathers during the pregnancy apart from
support the mother with the changes she is going through

After the birth, then hold on, the ride is now beginning and everything you
ever know is turned upside down

~~~
bluntfang
>I don't think you can equate

GP is not equating, and explicitly says so in the first real sentence of their
post:

>The experience itself is different.

------
theboywho
Has there been any studies on adopting a baby? Does it yield the same results
on men? If yes, then it might as well be a matter of social construct, where a
new vulnerable addition to the group needs protection for example.

Another curious question, it would be interesting to see the impact of
adopting a cat or a dog on men’s testosterone levels.

~~~
keymon-o
I'd guess the idea of this study is not that having a child of your own
somehow directly alters your brain biologicaly, but the experience itself is
just that intense. I find it much more interesting, the fact that most of the
changes mother experiences might not be the "nature's wonder", but lasting,
painful, traumatic and exciting experience itself that affects one's brain.

Edit: And that itself has much deeper relation to a biological child than to
adopting one. Not that adopting isn't significant or emotional, it's simply
not that varying level of experience.

> Another curious question, it would be interesting to see the impact of
> adopting a cat or a dog on men’s testosterone levels.

I would compare this analogy to the opposite and unfortunate experience like
the death of a close one. Losing someone that's biologically linked to you can
be really hard even if you weren't that emotionally attached to that person.
By comparing that to losing a friend outside of your family circle, which is
also a very harsh experience, it seems that biological line would be an
emotional line deeply attached to a person no matter what experience one has.

~~~
drclau
> And that itself has much deeper relation to a biological child than to
> adopting one. Not that adopting isn't significant or emotional, it's simply
> not that varying level of experience.

How do you know your child is actually biologically yours? Human fathers have
no biological/natural means of identifying a child as theirs. So your
hypothesis that having your own child va adopting is different does not stand.
The father - child bond is a mental construct and I see absolutely no reason
why adopting is lesser than biologically fathering a child.

~~~
NateEag
When conceiving children biologically, if you do not have reason to believe
your partner has had sex with other men, the natural assumption is that the
child is yours.

Also, family resemblances do exist. Their absence doesn't disprove parentage,
but their presence is evidence for it.

When adopting, if you were not sexually active prior to adoption and have not
donated sperm, you can be certain the child is not biologically yours. Even if
you were active or a donor, you can still be very confident the kid is likely
not yours.

I think adoption is a wonderful thing and I am not trying to undercut it, but
it seems entirely possible to me that those differences could impact the bond
between a father and child.

~~~
keymon-o
Exactly. Stating that an adoption is same as having a child of your own, is
going against all empirical evidence that a person has great emotional changes
upon finding out about your own biological relation to someone. Maybe it is
entirely psychological, but idea of a biological relation affects a person a
great deal.

I think most of the confusion here is coming from the idea that psychology
can't be related to biology. However, I firmly believe that biology is the
base of the psychology and you cannot alter psychology without altering the
biology itself.

------
lnsru
After becoming father I experienced biggest weight loss ever. I went from 260
lbs to 200 lbs. During the months not being chained to a table with computer I
was living healthy life. Lots of time outside with stroller or baby carrier,
healthy food for baby and me. Few years later I am at 220 lbs again.

~~~
gwbas1c
That happened with #1. Then #2 came, and the extra time getting both ready
meant less time for walks, so I gained it all back!

------
agent008t
So, reading this thread is making me really not want to have children. Seems
like one would have to be completely insane to voluntarily sign up for that.

People that have children. Do you think it was honestly a good idea in
retrospect, and if so, why? If your wife had been on the fence about having
children, would you have preferred to go child-free, in retrospect?

~~~
martythemaniak
Imagine if you just read about the negatives of Ivy-League schools - the
insane admissions process, the cost, the pressures, the depression, the sleep
deprivation, the drug abuse, the suicides, etc. You'd think people must be
crazy to go there, yet when you weight it against the benefits, it turns out
that basically anyone that can go there, should go there.

I think parenting, like school, is also a very high-effort, high-reward
activity. Maybe while the negatives are easy to understand, the rewards are
not so easily understood. "Give life to your offspring" just doesn't have the
same ring as "make a ton of money" or "become the ruling class".

~~~
ImprovedSilence
Honestly I’ve loved every second of it. Granted, Ive only got one, and she’s
pretty easy going so far and never had problems sleeping the night once she
was out of “needs food every 2 hr stage”. Yeah, things change, I don’t go out
to the bars to socialize as much (or at all) any more. Most of my friends
don’t have kids yet (but some do). Having said that, I need to constantly be
“changing” or “growing” in life. There are only so many years I can go
drinking with friends every weekend until it gets boring and I need a new
adventure in life. I travel less too, but still made it to Europe for a week
this year (with baby in tow). Your life doesn’t have to stop, but the things
you do change. And yeah, I love it. I am also not usually one of the ones that
bemoan all the lost sleeep or what have you in comments here. I would imagine
I’m not the only one who stays positive.

------
jl6
Weight gain has been the most obvious impact for me, but that’s probably a
consequence of a collapse in willpower/discipline as a result of sleep
deprivation and stress.

------
m-i-l
Anecdotal I know, but when my first was born and I was outside with them for
the first time, I got a weird sense of extreme overprotectiveness -
exaggerating somewhat to make the point, but it almost felt like I would punch
anyone if they looked vaguely threateningly at my new child (a particularly
memorable experience for me because I'm usually such a placid person). Not an
expert, but that felt like it could be something hormonal.

And at risk of sounding a bit handwavy, I think I've adapted to being a parent
much better than I thought I would, which I guess could be thanks to some
biological help.

Also used to look a lot younger than I actually was, and now I look my age or
even older, but that could simply be lack of sleep.

~~~
CodeCube
same ... I'll also add that for a time, I became hyper-aware of literally any
noise that happened anywhere in my house at night. Lol, I can't tell you how
many times I jumped out of bed to fend off an imagined intruder, or to run
into the baby's room to make sure she was still breathing :P

------
anonu
I am 14 months into kid #1. I've observed friends and family who are well into
kid #2.

My thought process was that going from 1 to 2 was going to follow some sort of
logarithmic increase in complexity - but I am now convinced that the change is
exponential.

With 1, you can split the work. With 2, the dad will probably be focused on
the older kid and the mom on the younger kid. Thus, there is less help to go
around.

Maybe at #3 there is some sort of loop-back effect where the older kid can
help out with the younger siblings?

Anyone with more experience care to opine?

~~~
Japhy_Ryder
> logarithmic increase in complexity - but I am now convinced that the change
> is exponential.

Good god. Is everything a math problem for you people?

It's called 'figuring life out'. Sometimes there's not a 'logarithmic increase
in complexity'. You just wing it. And you figure it out.

~~~
jriot
If we did that, 90% of HN articles wouldn't exist.

Though I am glad someone has similar thoughts as me!

~ Cheers

------
sgt101
>2014, Dr. Pilyoung Kim, Ph.D., a developmental neuroscientist at The
University of Denver, put 16 new dads into an M.R.I. machine: once between the
first two to four weeks of their baby’s life, and again between 12 and 16
weeks

16 examples -> I would set more store by tealeaf reading.

~~~
distant_hat
Underrated comment. Especially with a technique like fMRI.

------
senectus1
I can still remember "feeling" the change in everyday thought process once my
1st was born.

It was so noticeable... like I'd just stepped into someone else's brain.
really weird.

~~~
Dwolb
Are you able to elaborate?

~~~
senectus1
Its hard to do so.

It felt like a mental "click" but not like you get when you have been trying
to solve a puzzle... it felt like a mental " gear change ".

My thought processes changed order or priority, Things that I felt were
important before were suddenly less important and I think I things from a
different angle (not just life stuff but problem solving approaches.).

its really hard to describe.

What I can say is that having a second didnt do a damned thing... lol whatever
change was going to happen only happened on the first.

~~~
jjakque
Do you mean like parental instinct? When you are in 'father mode', you
physically and mentally geared up and ready to take up the role.

~~~
senectus1
My first thoughts were that it was like that, but I realized after a few weeks
that I was thinking like that at work as well, when nowhere near the kid.

~~~
jjakque
I think you may have got better at managing both your tasks and time :)

Very possible that been a father cornered you to think more pragmatically in
daily life, and that translates to how you do things at work.

------
johnwheeler
“a widespread and deeply ingrained belief among fathers: that because their
bodies haven’t undergone the myriad biological changes associated with
pregnancy, birth and breastfeeding, they’re not as biologically and
psychologically “primed” for caretaking as women are.”

I doubt that this concern is “widespread”. Sounds like the author creating
unnecessary urgency for an already interesting topic.

~~~
happytoexplain
Really? To me, that seems as obvious a majority thought as the more general
"women are more child-oriented than men".

~~~
johnwheeler
I didn’t lactate and therefore I’m not as psyched to be a dad? I’ve never seen
(nor felt) any such phenomenon.

~~~
Broken_Hippo
I'm female and have never wanted children. I never want to be pregnant. I'm
41, and have no children.

But I have had folks try to make me feel like I*m doing something wrong for
not wanting children - both men and women. Apprently, that's what I'm supposed
to want.

------
Kecelij
"University in Israel suggested that the parts of the brain that light up the
most are startlingly different for each parent."

Startlingly? Almost like every person was different..

~~~
chewxy
'each' here is bound to a specific instance of a pair of parents - i.e. "...
are startling different for the mother and the father"

English is not a good language

~~~
whenchamenia
This is a problem with how its written, not an entire formalized language.

------
hawski
I've got Tinnitus. I should have used ear plugs or rather a heavy duty hearing
protection much earlier.

My daughter had problems with her stomach or with us trying to put some
clothes on her. The scream amplitude and frequency in a small bathroom are a
horrendous combination.

I joked at the time that she sounded like Nazgûl.

~~~
war1025
Our youngest daughter screamed something terrible for months and months when
she was a baby. There was a period of maybe two months where I thought I had
permanent hearing loss from it.

Went to the doctor and turned out that I had a cold as some point and the
pressure in my ear never equalized back correctly, which meant the ear drum
couldn't vibrate right. A couple weeks of allergy medicine seemed to fix the
issue.

Around that time though, I bought a pair of ear muffs and wore them every time
I had to put her to bed or change her diaper. Amazing. Highly recommended.

------
MichaelMoser123
[https://nobaproject.com/modules/hormones-
behavior](https://nobaproject.com/modules/hormones-behavior) here it says that
a change in hormone levels can trigger a change in behaviour, but on the other
hand it can be the result of changed behaviour. For me as a laymen it is not
clear how to read all this.

------
blokeley
Interesting article.

1\. It doesn't mention obvious potential causes to brain changes and hormone
levels that coincide with having children like lack of sleep, changes to diet,
or adjustments to work patterns etc.

2\. It says towards the end that I should continue to wrestle the boys. Great!

------
chayesfss
Father of 5 here, during first 2 I was right there, gained a lot of weight
slowly but identical twins @ 43 I am surprised there had actually been a
weight drop.

It has been amazingly difficult with twins, for the first 6 months it was pure
hell. I didn’t really sugarcoat it when people asked, yes it’s hell, no it’s
not fun. People were much more understanding of the my sour attitude with
twins.

Many people both get up as a sign of support but yea it’s stupid, after some
time we found that taking turns getting up has allowed the other to get some
sleep, surprised we didn’t get any guidance from the hospital on this subject
at all while at the hospital.

------
ademup
"Certain areas within parts of the brain linked to attachment, nurturing,
empathy and the ability to interpret and react appropriately to a baby’s
behavior had more gray and white matter between 12 and 16 weeks than they did
between two and four weeks."

For you father-programmers out there: did you notice any changes in your
programming/work abilities around the 12-16 week mark?

~~~
muzani
I always took off 3 months from work per baby. There's no point coding when
you're always sleep deprived. Last year the company agreed to about half the
salary, so I'd work from home on some things, or come in half the week or half
a day as needed.

Then again I did notice I was very good at understanding baby talk.

Taking from some old notes of my 5 month old baby:

"eh eh eh", but no crying at 6 AM = "I need a diaper change" or "I'm hungry"

rapid kicking = excited

wide open arms while lying down = "pick me up"

"uh huh/mmm" with slight head inclining = yes.

when mother is saying something, baby laughs, turns head towards me, "uh
huh/mmm" with inclined head = "mother is right" or "I told you so"

laughing and turning away = "I like that"

licking lips = "I want to eat whatever you're eating"

"aaaaaaaaaaa" = conversation or song

long, drawn out, angry crying = "I'm tired and I don't know how to sleep"

~~~
yitchelle
You could extrapolate that into an app. :-)

But seriously, congratulations on getting to that level of bonding with child.
It was also the same for me and it is magical!

~~~
muzani
It's quite different to the first kid so I don't think the same translations
work with most other kids.

------
peteridah
This has been a very useful thread.I have struggled with weight for many
years. I have sufficient motivation to exercise and I am normally able to keep
a disciplined schedule. But with our 2yr old daughter, sleeplessness has kind
of messed me up and I struggle to keep any form of discipline now. It's hard.
I am just glad to know that I am far from the only one :)

~~~
randlet
Exercise helps a bit with weight, but the overwhelming factor in weight
loss/gain is the amount of calories ingested.

------
mirimir
Maybe it's just my biology training, but that was obvious to me decades ago. I
mean, why should humans be different from other mammals, regarding such a
basic thing?

It's also part of why I never wanted kids. That, and the threat of global
nuclear war.

------
KaiserPro
my changes:

o hair loss (Eldest's birth and early life was traumatic)

o Loss of short term memory (mostly temporary, sleep loss related.)

o loss of hearing (eldest was fond of screaming)

o grey hair.

We split child care into two shifts. I took nights, wife took days. Hence why
I had less sleep than the wife.

~~~
nradov
It seems unlikely that a child could scream loud enough to cause significant
hearing loss.

~~~
KaiserPro
Babies can scream at 120db. (supposedly 130, but I find that hard to believe)

not only that its at about 3.5khz. now look at this graph:
[https://en.wikipedia.org/wiki/Equal-
loudness_contour](https://en.wikipedia.org/wiki/Equal-loudness_contour)

Right in the loudness contour.

children, less so, babies yes.

number two is nowhere near as loud or as prone to screaming

~~~
Japhy_Ryder
> Babies can scream at 120db. (supposedly 130, but I find that hard to
> believe)

That sounds absolutely terrible. I am not looking forward to having a kid. :-(

~~~
KaiserPro
ahhh You'll do fine.

I was unlucky, I had a screamy one. The second child barely cries at all.

------
danieltillett
No study that relies on self reporting can be trusted.

------
gwbas1c
Honestly, the dopamine rush that I feel when I rock my kids is stronger than a
cup of coffee.

------
ijiiijji1
Random Q: I have to lose 40 lbs getting dad-bod sans dadness right now
(medication side-effects).

0\. Has anyone seriously looked into variations of intermittent fasting &|
extended fasting?

1\. Did you have brain fog after hunger went away after a few days, or less
fog?

2\. What about maintenance vitamins, electrolytes and preventing gallstones?

3\. How long did you continue for, until hunger returned?

~~~
btmiller
Most reliable method in my own experience: simply eat less.

Eat your normal amount of meals, shovel it in your mouth, but stop before
finishing the whole portion. I eat maybe 75% of each meals and toss the
remaining bits. Do it for a couple months and watch the weight magically shed
off.

It works because it requires no change in meal-type habits; it’s simply fewer
calories. End of the day, that’s always the goal and this way is the most
direct and simple

When the meals come where it’s hard to stop at 75%, I force myself to toss my
napkin and utensils on the plate ensuring the food is now “dirty”. So
altogether, it’s very few behavior changes make for a foolproof method.

~~~
bambataa
Can’t you just serve yourself less food rather than deliberately wasting a
quarter of it?

~~~
DomreiRoam
It is quite rational but it's difficult to be rational when you're hungry;
it's easier to cut on food when you have calm down your stomach. Like don't go
shopping when hungry, you will buy more unhealthy food.

------
Ancalagon
I'm curious what the relation between child-rearing and balding might be, if
any. The old-wives tale is that men needed to be evolutionarily "pushed" to
settle down, and actually take care of their kids. I would think a drop in
testosterone would actually have the reverse effect though, and reduce balding
for those susceptible to dht.

~~~
dogma1138
What does balding have to do with settling down? Women really don’t seem to
care nearly as much as men do...

~~~
jsiepkes
That has not been my experience. During my dating period (about 5 years ago) I
was regularly told that my full head of hair was a pre. Though there could be
bias there since the ones who care obviously were more likely to seek me out.

~~~
rolltiide
My experience is that women - like men - have preconceived notions of
attraction that are easily circumvented, to make you more overall attractive
_enough_.

Full head of hair is a qualifier, without it different things are needed to
get yourself an in. The same logic goes for many attributes are considered
qualifiers that aren't.

Yes, there are some men that expend very low energy and have women seemingly
flock to them. I've seen bald men in this circumstance, and full haired men in
this circumstance, I would say it is a very low weighting on anything.

Bald _ing_ though seems to function different than bald.

------
techie128
I am sure the author means well. However, this makes little sense from an
evolutionary standpoint. Although humans have evolved far more than most
animals on this planet, the basic idea of evolutionary biology remains the
same. In the wild, males have to hunt (provide food), protect the new born(s)
and their mate(s) from threats. Therefore having the same level or higher
levels of Testosterone is a biological imperative. Testosterone makes the male
stronger and more aggressive. Both are very useful traits from an evolutionary
standpoint. I cannot imagine human males diverging too much from this basic
framework.

Coming to today's workplace, after childbirth there is a drop in productivity
of male employees as they adjust to their new reality. However, I have
observed men become more diligent and aggressive at their jobs. I only imagine
thats because they have a stronger sense of responsibility to provide for
their partner & offspring. Whether or not Testosterone levels change is a
different matter.

~~~
kristiandupont
>this makes little sense from an evolutionary standpoint

I am certainly no expert on this area but it sounds to me like you are
concluding that the study must be invalid, based on a bit of armchair science.

~~~
techie128
The ideas I have presented are not 'armchair science'. They're widely accepted
in the field of evolutionary biology.

~~~
marchenko
Evopsych explanations can often be used to argue both sides of any issue. For
example, T is implicated in male aggression, which is useful when fending off
predators both animal and human, but dangerous when you have a helpless, often
_extremely_ irritating Bundle of Evolutionary Fitness around. T is also
thought to be involved in mate-seeking behaviour, which one may wish to
downregulate for a while after successfully reproducing in order to devote
resources to infant survival. Testosterone is also metabolically expensive,
and those costs may be paid at the expense of the immune system. It might be
advantageous to upregulate immune functions when an immuno-compromised neonate
is around. You and the author could both be correct, but neglect important
components of the testosterone fitness package.

