Welcome to Chasing Life. You know, I have taken on a lot of different roles of my life. I've been a son,

I've been a husband, a neurosurgeon, a journalist. But you know, when I really think about it,

I think being a dad to my three daughters is the most important role in my life. No question about it. Because I think no matter

how busy things have become at times, that is the role that I always come back to. That's the

role that seems to anchor everything else in my life. And my girls have gotten older now. Two of them

are out of the house. I got one more who's starting her senior year now in high school. They've started to move on with their life. And as a result,

I think it's really made me reflect on fatherhood in a new way. I think when you're in it,

life is just so procedural. You're getting through one day to the next, sometimes just one

hour to the next. But at this stage

of life, you get a chance to reflect. And I've been thinking a lot more about how being a dad has

changed me. How am I different? Not only emotionally, but maybe even ways that I'm not even fully

aware of. And my guest today has been thinking about this for a long time as well,

has been studying this for years. Dr. Darby-Saxby is a psychologist at USC who has been

researching what happens to men as they become dads. How do their brains change? How do their

hormones change? What happens to their mental health and to their other

relationships? She is the author of a new book. It's called, appropriately, Dad Brain, the new

science of fatherhood and how it shapes men's lives. So today, Dad Brain, what is really

happening to men when they become fathers and what might we all learn from this?

I'm Dr. Sanjay Gupta, CNN's chief medical correspondent.

And this is chasing life.

The internet is coaching our kids.

When boys hear that on repeat, it shapes how they see themselves.

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