HAVING A CHILD CAN CAUSE YOUR BRAIN TO SHRINK?

The Diary Of A CEO

  • Aug 24, 2026
  • 1:36
  • Short

A man’s brain can shrink by around 1% when he becomes a father.

I’ve seen how much fatherhood can change a man’s life. I had no idea how much it was changing his brain too.

So I sat down with Dr Darby Saxbe.

Darby is a Professor of Psychology at the University of Southern California and one of the few researchers in the world who has tracked what happens to men’s brains as they transition into fatherhood.

Her research revealed something I had never heard before: becoming a dad literally rewires your brain. And the more involved a father is, the more pronounced those physical changes can be.

We discussed things like:

- How becoming a father can physically reshape parts of the male brain. - The surprising effect having a baby can have on a man’s testosterone. - Why some fathers experience postpartum depression. - What having a child can do to even a strong relationship. - What new fathers can do to become better, more confident parents.

What I liked about Darby is that she isn’t just interpreting other people’s research. In her own lab, she has followed first-time parents from pregnancy into parenthood, scanning fathers’ brains, measuring their hormones and studying how couples change before and after having a baby.

Something I found myself coming back to afterwards was how easy it is to see the trade-offs of having children from the outside. The sleepless nights, stress, financial pressure and sacrifice are obvious. The meaning, connection and sense of purpose that parenthood can create are much harder to see. Darby’s work gives us a much clearer picture of both.

If you’re a parent, might become one one day, or simply want to understand why parenthood can change people so profoundly, I really recommend this conversation.

Out now on all platforms ❤️👊🏾

Brief Summary

Fathers experience brain changes and testosterone drops; advice for new dads is shared amid concerns about declining birth rates.

Key points

  • Surprising Brain Findings. Research shows fathers experience brain shrinkage but also have markers of a younger brain age.
  • The Popularity of Dad Bods. Studies reveal that dad bods are the most popular body type among single women.
  • Declining Birthrate Concerns. The US fertility rate has hit an all-time low, raising concerns about parenthood choices.
  • Transformative Parenthood. Becoming a parent is a significant transformation that brings connection and purpose.

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