Decreasing Sperm Count

I was very pleased to see that Stuart and Tom had devoted an episode to this over at The Studies Show. As they often find, what everyone is panicking about does not seem to be as big a problem as advertised, never mind what we have got to do to fix it. I'm certainly not worried for myself, and even with my sons the issue is progressively less important each year. JA is 38, his wife 32, but they have three daughters, so no frightening issue. Kyle is only 28, maybe I should be worried first for his sake if there is some plastic that is making the frogs gay. And there are still some nieces and nephews, and of course the granddaughters, and we don't want loved ones to be sad over fertility.

For openers, there are problems with the data, and have been for decades. Many of the studies are drawn from people coming in to hospitals or fertility clinics because they or their spouses are having problems conceiving. That's not a natural sample. Nor is it the same over time.  As IVF becomes more common, less expensive, and more available, people are coming in to clinics now who might not have bothered thirty years ago. Next, the comparisons over time are mostly from countries and even regions where the population age is rising. Complicating that further is that more people now have access to good health care and are healthier in many ways.  OTOH, there is more diabetes and metabolic syndrome now. There are even variations in sperm count in single individuals in different seasons of the year. Sperm is more dense in the winter. So if you are doing reviews of previous studies, that data may not even have been tracked.

Then there is the counting of sperm density in semen...

Obtaining human semen for scientific analysis is logistically difficult. If collection of semen samples were as straightforward as obtaining blood samples, the nature of semen quality changes over time, if any, would have been determined decisively decades ago...That's because you have to bring people in and they've got to...uh...masturbate Yes they do, let's not beat around the bush so to speak...It's actually, it's not a straightforward thing, like the WHO guidelines on how to produce good semen samples.  Anyway, there are guidelines to how you...But for example, you're supposed to dilute the sample to stop the sperm swimming away.  Fewer than 8% of clinical laboratories actually do that according to - I think that was according to Fisch.

Lab techniques differ.  What counts as healthy sperm morphology has gotten more strict. Different laboratories counting differ by as much as two orders of magnitude on the same samples. So what do the numbers even mean? Yet it is one thing to merely say that "everyone else's numbers just aren't very good," which leaves us nowhere, and claiming that the better the studies are, the less effect they show. Criticisms of the meta-analyses have reduced the number of retrospective studies from 68 to 6 good ones, which show little effect, and the five best prospective studies show effects so mixed as to be essentially zero. *

A few minutes of transcript, and they are now talking about science in general. We yawn at the conclusions of studies which always say "more research is needed," but sometimes these are not just the polite, industry-protecting boilerplate we treat them as.  Increasingly, authors are describing what kind of research should be next in this field.

A: I know it's sort of a very pious thing to always say, a call for more studies.

B: But that's what everyone does.

A:You know, and Augur says we need repeated prospective multicenter studies looking at a large representative sample of the population.

B: There haven't been any, so there just aren't. The sort of perfect study is still yet to be yet to be done.

A: And maybe it will never be done because it's really difficult to do.

B: The thing is, it seems like a really important question.

A: And I think there's enough like hints.

B: This is what I said in my article I wrote last year or earlier this year on this topic, is that there's enough hints that we need to do a proper study on this.

A: And it would seem to be quite important for the, you know, the future of humanity and stuff.

B: But it's another case where scientists have sort of failed really, you know, like, you've had decades and decades and decades of research on this, and we still don't know the answer.

A: And there's so many cases like that.

B: And it shouldn't be the case that we have decades and decades of research on any question.

A: And we're still completely baffled by it, of a question that's, you know, we're not talking about working out the answer to fundamental physics here, or, you know,

B: No, it's counting sperm.  You're literally counting sperm...

A: It's not quantum gravity, is it?

B: No, no, no, exactly.

A: You feel like there'd be, you know, maybe it would take you 10 years and or 20 years and but… 

B: Right, someone like dedicating their career, someone who really cares about solid inferences and who has resources and wants to do this and, you know, you'd think that there would be someone would want to fund that and

A: I'm just a bit baffled as to why we have this whole morass of rubbish research and we're trying to discern patterns in the tea leaves of that when what we really want is high quality research.

We sometimes want to search for explanations before we are quite certain the phenomenon even exists. I fell into that myself.  I was already wondering if the suggestion that the reduced hours of sleep in modern populations was the cause. Well, first catch your rabbit. Is there even really an issue at all?

*They do not like the Shanna Swan book, Count Down, BTW,  and I have immediate suspicions myself. The blurb at Amazon begins "In the tradition of Silent Spring and The Sixth Extinction..." Yeah, hard pass on that.