Global sperm counts have declined by over 50% in the last 40 years. Is that true?

You know, it really is. I think, you know, in the last few years, there's been a lot of consensus around that.

You know, one of the most famous studies that looked at this was published in the 90s.

And, you know, when it was released, I've talked to some of the authors about it. There was a lot of fainfare around it. You know, they had it in a big media hall. There were television cameras. But since then, there was a lot of controversy around it. You know, for a few reasons, you know, there are differences in semen quality around the world. Like, for example, there's a study in the United States that showed, you can believe it's sperm quality is higher in New York than the Midwest. And I think reasons for that are not certain, you know, whether it's lifestyle, you know, activity levels, there may be differences and, you know, just sort of race ethnicity composition. I think the reasons are not known. But in the U.S. we see that,

but around the world we see that too. And so there were some concerns about how all that was

incorporated to some of these studies. You can imagine over 40 years, some of the methodology

for testing sperm has probably improved a little bit. And even our statistical methodology is

computational abilities have improved. So, you know, initially in the

90s, I think it was somewhat controversial, even some of my mentors question this. But I would say over

the last, you know, few years, there's another study in 2017, than even 2023 most recently,

and it's really kind of solidified. And now there's consensus in the field that we're seeing this

decline. You know, over the last 50 years, maybe it's called about 1%, so maybe about 1 million less sperm per year on average every year. But over the last, you know, 10, 20 years, it's accelerated actually about 2% decline. And so I think it's, you know, now that there's a little more, you know, again, sort of consensus around it, I think it's really up to us to understand why because, yeah,

it's, you know, now that there's a little more, you know, again, sort of consensus around it,

I think it's really up to us to understand why, because, yeah, it's not a good thing,

existential, I think, in a lot of ways. Okay. Why do we think that this is happening? Beyond the

ability to detect statistical improvements physically, what's happening? Yeah, I mean, I think

that's the million-dollar question, or billion or or trillion dollar question, really. I think there could be a few reasons. You know, the pace of change is probably too quick for evolution. I don't think it's a genetic factor. You know, so I think people have really honed in on exposures, you know, whether it's, you know, lifestyle factors. I mean, I think that, you know,

probably a little less sedentary than we used to be, you know, obesity was going up, although maybe with some of the new medications, we'll see reversal of that trend. But I think there's a lot of concern about just some of our exposures, you know, some of the chemicals in the environment, microplastics, I think those sorts of things. You know, there's some endocrine disrupting factors that are at play here that may be the culprits. But I think, you know, we need to really do more

work to try and understand it. And I think that's kind of where we are. So you at the forefront of

this have a broad perspective that stuff's not great. Numbers are going in the wrong direction.

We kind of have an idea of what's going on, but are going in the wrong direction, we kind of have an

idea of what's going on, but actually finding an individual target or a couple of targets that we could intervene with, it sounds like a pretty complex problem to try and solve. Yeah, I think that's fair to say. I mean, I think there's, you know, there's things that we talk to patients about, I think, just sort of broadly when they come into the clinic, you know, obviously, you know, patients come to see me for fertility.

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