Dr. Peter Attia

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5,258 appearances 36 recordings 6 series first heard Jan 2024 last heard Jun 2025

Dr. Peter Attia’s voice in public audio — every appearance, attributed to the second.

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The Peter Attia Drive · #351 ‒ Male fertility: optimizing reproductive health, diagnosing and treating infertility, and navigating testosterone replacement therapy | Paul Turek, M.D. · 2 Jun 2025 podcast

I was like, they're just as thick. So I buy one of those. And every time I encounter the word meiosis and mitosis, I assume it's a spelling mistake because I bought the knockoff book. So I'm treating it as the same thing. Every time I see the word meiosis, I'm like, these guys, they just misspelled it, idiots. It's mitosis, mitosis, mitosis.

Finally, on the night before the exam, which I still remember, August 17th was the day I took the test. I realized they were two totally different things. Big things. Oh my God. That realization might've got me into med school because I think I barely got a 10 on the biology section, which was, it's hard to get into a good med school if you get below that.

So anyway, to this day, I get such a chuckle out of The confusion of the nomenclature. But again, just to explain for people, mitosis is what happens when cells are dividing in our body constantly where they're trying to create a perfect replica of the entire suite of DNA. So really, to my knowledge, the only time we're undergoing meiosis is in the creation of an egg or a sperm. That's right.

Okay. Now, remind me, are women born with all of their eggs? I feel like that's something I vaguely remember.

But sperm are constantly renewed. Is that just a mass space problem? Because the testes, if we did the same thing women did, would we just have to have an enormous set of testes? Why do you think out of the box like that? No, I'm not sure. I mean...

That's an interesting point. So it's transgenerational. Does that mean that the father is more likely to pass on environmental stressors than the mother? Probably, yeah. And that's definitely been shown. Okay, so let's go back to it. So the sperm is the actual cell. Where does it get the little tail from and what is the other part of the cocktail that is...

Is there any other cell in the body that is capable of that?

And a man potentially has access to this cell his entire life? Yep. As long as he's making sperm.

Actually, let's focus on that for a second. I hadn't considered that. So when the cell that is becoming a sperm undergoes meiosis and it divides, what's the fraction of times when this becomes an aneuploidic sperm? And explain maybe to people what aneuploidy is and what's the process by which that thing gets discarded?

So something is getting filtered. So there's a filter. Yeah, and just so folks know, when we say aneuploidy, we mean you don't have one copy of each chromosome. You either have none or you have two or anything that's not one is bad. Right. When aneuploidy occurs in the fusion of the sperm and the egg, do we know, I guess we can figure out pretty easily if it's maternal or paternal in origin?

If you look at the embryo, it's kind of hard to tell.

So this is a man who's XXY instead of XY. So 47 chromosomes, not 46. Yep. And phenotypically, he kind of has a distinctive look, right? 10% of the time. Oh, really? 90% of the time, a man with Klinefelter's, you'd never know. Yeah.

So that's the board question. That's the board question, right?

Meaning they will produce an X or a Y sperm. Just like everyone else. The only difference is they have a two-thirds chance of producing an X and a one-third chance of producing a Y, I'm assuming, instead of 50-50. Don't think we know that.

I interrupted you. You were in the process of explaining how we actually make the sperm, where the tail comes from and the whole process. Yeah, it's all done in the testicle. Yep. It's an amazing machine. Weird question we should maybe get to is why is it out in the breeze like that? I assumed it was temperature related. Why? Why does it need to be a little cooler?

I would guess, because I like to make things up, that it's so energetically demanding that it's giving off more heat in the process of creating something that is going to be so efficient to be able to swim 20 miles effectively. And that's very glycolytic, I'm assuming. The amount of ATP that must be generated. 75 mitochondria for sperm. That's like an electric motor on each wheel. Yeah.

So that would be my guess is it's an overheating problem if you tried to keep those guys inside. And I think overheating could be translated to oxidative stress, which is a cause of a lot of infertility.

Women can get in hot baths and they're okay. It's funny. I had a buddy over who shall remain nameless. He does not have kids, but he would like to have kids. And we sauna'd the other day. He went up to my freezer beforehand. I didn't really know what he was doing in there. I thought he was getting a drink or something. And he came down with ice packs.

We were sitting in the sauna and he was in the sauna, but he's got ice packs all over his groin. Immediately understood why he was doing that. But yeah, we'll come back to whether or not that's an important strategy for men in saunas who want to have kids. So the complete sperm, spermatogenesis is the whole process.

Give us some size comparison. Before the tail is on, what is the size of that cell? Probably similar to half the size of a lymphocyte or half the size of a red blood cell, a couple microns.

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