Testosterone Expert: The Truth About DAD BOD & Why Women Find Fathers More Attractive!

Aug 24, 2026 Transcript ↗
Overview

Dr. Darby Saxbe, a psychology professor, reveals the "parental brain" science, detailing how fatherhood reshapes men's brains, hormones, and relationships. She also discusses societal impacts on birth rates and offers practical advice for new parents.

At a Glance
11 Insights
1h 28m Duration
24 Topics
10 Concepts

Deep Dive Analysis

Introduction to the "Parental Brain"

Father's Brain Shrinkage and Increased Efficiency

Maternal Brain Changes and Biological Investment

Cultural Influence on Fatherhood Engagement

Testosterone Drop in New Fathers and Its Adaptive Role

Fatherhood's Profound Shift in Values and Priorities

The Visible Downsides and Invisible Upsides of Parenting

Couple Conflict During Pregnancy and Birth Outcomes

Why There's No "Perfect Time" to Have Kids

Global Declining Birth Rates and Societal Impact

Neuroprotective Benefits of Parenthood for Brain Health

The Role of Oxytocin and Social Bonding

Daycare, Alloparenting, and Attachment

Maternal Gatekeeping and Weaponized Incompetence Dynamics

Relationship Satisfaction and Intimacy After a Baby

Understanding Paternal Postpartum Depression

Cortisol Interconnection as a Divorce Predictor

Concealed Ovulation and Human Pair Bonding

Comprehensive Advice for Expectant Fathers

The Adaptive Significance of the "Dad Bod"

Personal Influence on Fatherhood Research

Human Monogamy: "Monogamous with Benefits"

Major Concerns About Modern Parenthood

Systemic Changes to Support Parents

Volume Reduction (Brain)

In the context of parenthood, this refers to the shrinking of gray matter in the brain, which is not a deficit but an adaptive process where the brain becomes more efficient by building better-connected pathways and consolidating information to focus on child-related inputs.

Facultative Adaptation

A biological adaptation that is optional but extremely useful, meaning it varies depending on cultural and environmental contexts. Fatherhood is described as facultative, as men's investment in parenting is modulated by what they learn from their environment.

Mentalizing Network

A part of the brain concentrated around the midline of the cortex, crucial for understanding other people's feelings and intentions. In new fathers, this network shows volume reduction, indicating improved efficiency in social information processing.

Alloparenting (Cooperative Breeders)

The concept that humans are a species designed to raise children in a community, with shared care from multiple individuals beyond the biological parents. This model evolved to provide support and reduce parental isolation.

Maternal Gatekeeping

A dynamic where a mother, consciously or unconsciously, creates roadblocks to a father's full participation in parenting, often by taking over tasks or not trusting his abilities, which can lead to dads feeling sidelined.

Weaponized Incompetence

A behavior where a partner, typically the father, feigns inability or lack of knowledge regarding household or childcare tasks, causing the other partner, typically the mother, to assume responsibility. This can lead to frustration and an imbalanced division of labor.

Perinatal Depression

A term for depression that occurs around the birth of a baby, applicable to both mothers and fathers. It acknowledges that the period following birth is a time of increased mental health risk for both parents due to various factors.

Concealed Ovulation

A unique human characteristic where female fertility cues are not overtly displayed. This encourages pair bonding and repeated sexual activity, fostering stable monogamous relationships and reducing male rivalry.

Proprioceptive Touch

A type of vigorous physical touch, such as picking up, moving, and playing with babies in space, often associated with fathers. This kind of touch can increase oxytocin levels in dads and helps children develop risk tolerance and emotion regulation skills.

Matrescence/Patrescence

These terms describe the profound psychological and identity transformations experienced by individuals as they become mothers (matrescence) or fathers (patrescence). It signifies a reordering of priorities and self-concept.

?
What happens to a man's brain when he becomes a father?

A man's brain loses gray matter volume, particularly in the mentalizing and visual areas, which is an adaptive process making the brain more efficient at processing social information and understanding infant cues.

?
Why does testosterone drop in new fathers?

Testosterone typically drops by about 25% in hands-on fathers, which is an adaptive biological shift that helps men transition from a competitive, high-testosterone state (for maximizing offspring production) to a nurturing, investing mode for child-rearing.

?
Should men be worried about lower testosterone after becoming fathers?

No, men should not be overly concerned, as masculinity is not solely about a particular hormone level. Flexible, mid-range testosterone levels are adaptive for fatherhood, and very high or very low levels can have downsides for relationships and mental health.

?
How does fatherhood change a man's personality and priorities?

Many fathers experience a profound shift in values, moving from material or career-focused goals to prioritizing their children and seeking meaning and purpose through their parenting role.

?
How does couple conflict during pregnancy affect birth?

When couples engage in more negative conflict behaviors (criticism, contempt, stonewalling) during pregnancy, they are more likely to experience medically complex births and appraise the birth as more stressful.

?
Is there a "perfect time" to have children?

No, there is no perfect time to have children; historically, having kids was a foundational life event that provided impetus for building stability, rather than a capstone achieved after all conditions are perfect.

?
Do parents have healthier brains in later life?

Yes, emerging research suggests that being a parent is neuroprotective in late life, with studies finding that both men and women who have had more children (especially two or three) have markers of a younger-looking brain age.

?
What is the role of oxytocin in parental brain health?

Oxytocin, the bonding chemical, is neuroprotective, actively downregulating harmful pro-inflammatory cytokines in the brain and enhancing brain plasticity, which can improve learning and memory as parents age.

?
Is daycare harmful for young children?

While very young babies (under 18 months) may benefit from a single caregiver, group care settings like daycare can be beneficial for toddlers (18 months and beyond) as humans are an alloparenting species designed for shared care.

?
Can fathers experience postpartum depression?

Yes, fathers can experience postpartum depression, with new dads having about twice the risk of depression compared to non-fathering men, due to a combination of hormone, sleep, identity, and relationship changes.

?
Can personality predict divorce?

While not a direct predictor, studies show that when couples have strongly linked cortisol levels (meaning they are contagious to each other's stress), they report lower marital satisfaction, suggesting that modulating stress is beneficial.

?
Why is human ovulation concealed?

Human ovulation is concealed, unlike in many other animals, to encourage pair bonding and repeated sexual activity, fostering stable monogamous relationships, reducing male aggression, and increasing altruistic investment in children.

?
What increases the chances of conceiving?

Reducing stress is important for conception, as stress makes it harder to conceive. Creating a calmer and safer environment, alongside optimizing nutrition, can help, though much is not entirely within one's control.

?
What is the "dad bod" and why is it attractive?

The "dad bod" refers to the mild weight gain men often experience as new fathers, which is an adaptive biological change. Research suggests women find it attractive as it signals a man is more likely to be a hands-on, attentive, and caring father.

?
What systemic change could transform parenting?

Building a better policy environment around parenting, specifically universal paid parental leave, would be a positive change, as the U.S. is a significant outlier in not providing federal-level paid leave.

1. Prioritize Relationship Communication Before Birth

Work on communication with your partner and discuss how to divide baby care responsibilities and core values (e.g., extended families, religion, education) before the baby arrives to prevent frustration and conflict and foster mutual trust.

2. Build a Strong Social Support Network

Actively build or strengthen your social support network with friends, family, and other expectant parents before birth, as loneliness and isolation are common challenges, and community support is crucial for alloparenting.

3. Embrace Hands-On Baby Care

Actively engage in all baby care opportunities, even seemingly unpleasant ones like changing diapers, as these moments offer chances to bond, build confidence as a parent, and develop attuned caregiving skills.

4. Protect Your Sleep Foundation

Establish healthy sleep routines and good sleep hygiene (e.g., dimming lights, optimizing room temperature, avoiding devices before bed) before the baby comes, as sleep deprivation will be a major challenge, and a strong foundation helps mitigate risk.

5. Give Yourself Parental Grace

Recognize that the transition to parenthood is profoundly challenging but temporary, requiring short-term sacrifices that ultimately lead to long-term fulfillment, meaning, and a richer life purpose.

6. Address Negative Conflict Behaviors

During pregnancy, focus on effective conflict resolution by conveying understanding and validating your partner’s perspective, avoiding criticism, contempt, or stonewalling, as negative conflict can lead to more medically complex births and increased stress.

7. Don’t Wait for the “Perfect Time” to Have Kids

Understand there’s no ideal moment for parenthood; historically, having kids was a cornerstone that motivated building stability, rather than a capstone after achieving perfection, and biology doesn’t always wait.

8. Be Flexible with Testosterone Expectations

Don’t be overly concerned about a drop in testosterone with fatherhood; it’s an adaptive biological shift that helps men switch into nurturing mode, and mid-range, flexible levels are optimal for both parenting and relationship satisfaction.

9. Engage in Vigorous Physical Play with Kids

Fathers, especially, should engage in physically demanding play like picking up and throwing kids (safely), as it helps children build risk tolerance and emotion regulation skills by practicing fear and relief.

10. Consider Shared Care for Toddlers (18+ months)

Group care settings like daycare can be beneficial for children aged 18 months and older, allowing them to thrive with social interaction and providing sustainable support for parents, aligning with our alloparenting nature.

11. Prioritize Couple Time Post-Birth (Early Newborn Phase)

Take advantage of the early newborn phase, when babies are more portable, to go on “date nights” (e.g., bringing the baby in a car seat to a restaurant) to protect relationship quality before children become less portable.

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.

Dr. Darby Saxbe

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.

Dr. Darby Saxbe

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 stuff is right in your face. But the upsides are sort of invisible...

Dr. Darby Saxbe

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.

Dr. Darby Saxbe

We are an alloparenting species. So what that means, 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 raise their kids. We are not designed to do this in isolation.

Dr. Darby Saxbe

It's like Sudoku 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.

Dr. Darby Saxbe

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.

Dr. Darby Saxbe

If you show women torsos of different kinds of male body types, the sort of dad bod is one that women say he's more likely to be a hands-on father. He's probably going to be more attentive. He's going to be more caring. And those are things that are really attractive to women.

Dr. Darby Saxbe

Preparation for Fatherhood

Dr. Darby Saxbe
  1. Take advantage of the window before birth to work on communication with your partner.
  2. Discuss how you want to divide up baby care responsibilities and core values (e.g., extended families, religion, education) before the baby comes.
  3. Build up your social support network with existing friends, family, and new community (e.g., other expectant parents, Daddy Stroller Social Club).
  4. Protect your sleep by establishing healthy routines and good sleep hygiene (e.g., dim lights, right room temperature, no devices before bed) before birth.
  5. Think of preparing for parenthood like running a marathon, focusing on overall health.
  6. Once the baby comes, take any opportunity to bond, like changing diapers, to get to know your baby and build confidence.
  7. Give yourself grace, knowing it's hard but temporary, and that sacrifices lead to long-term benefit.
  8. Prioritize date nights, even if it means bringing a newborn in a car seat to a restaurant, as newborns are more portable.
2.5%
Maternal brain volume reduction Amount of brain volume mothers lose from before pregnancy to after birth.
1%
Paternal brain volume reduction Amount of brain volume fathers lose in studies.
2.2 children per woman
Global fertility rate (today) Down from an average of 5 children per woman in 1950.
1.6
U.S. total fertility rate An all-time recorded low, far below the replacement rate.
2.1 children per couple
Population replacement rate Required to keep the population stable without immigration.
1%
U.S. birth rate drop (2025) Continuing a nearly two-decade downfall slide since the Great Recession.
1 in 2
Children born in Sub-Saharan Africa by 2100 Predicted proportion of all children born on the planet.
2 or 3 kids
Neuroprotective benefit for brain age The number of children after which the benefit seems to level off.
18 months and beyond
Optimal age for group care (daycare) Age at which kids can benefit from social interaction in group care settings.
Twice that of general population
Paternal depression risk New dads have this risk compared to non-fathering men.
12 weeks
Federal parental leave (U.S.) Guaranteed unpaid leave under the Family Medical Leave Act.