You know, despite many years of practicing medicine and reporting on medicine, I am continuously

reminded that the body is still full of mysteries. Remarkable mysteries. We haven't figured out

how to stop aging or even why we really do age. We haven't cured cancer. There's really so much

about our bodies we don't know. Big fundamental questions.

And yet, at the same time, we've made real progress. Progress worth celebrating. We can replace

hips and limbs and heart valves and so much more. Just the whole notion of replacing pieces of

ourselves. How do we do that? Why do we do it? Where are we at?

That's one of my favorite science writers, Mary Roach. You're in for a treat today.

For years, she's explored big questions about the human body.

She's written about cadavers in her book Stiff.

The Science of Sex in her book Bonk. Yeah, she comes up with clever

titles. And even wrote about what happens to us in space in her book called Packing for Mars. This time,

however, she's turned her attention to humanity's long fascination with replacing body parts. And the book

is called replaceacable You.

So I really wanted her to come on the show. She accepted the invitation right away.

We're going to talk about what breakthroughs are already changing lives, what's still a work

in progress, and what it really means to replace parts of yourself that work

just as well, or maybe even better. I'm Dr. Sanjay Gupta, and this is chasing life. AI is incredible.

They can teach you how to fry an egg and even write a poem, pirate style.

But it knows nothing about your work.

Slackbot is different.

It doesn't just know the facts.

...