Don’t panic, sperm crisis not yet upon us, not even looming

“I tried counting mine, but I went blind with exhaustion,” tweeted one reader of the BBC website after it reported that sperm counts were down by half in the past 40 years in the developed world. And it’s true: they are hard to count. The little buggers won’t stay still.

The report, published by Human Reproduction Update on Tuesday, is the work of Israeli, American, Danish, Spanish and Brazilian researchers who reviewed almost 200 studies done in different places and times since 1973.

It’s called “Temporal trends in sperm count: a systematic review and meta-regression analysis” and the authors are working hard to get the world’s attention. Dr Hagai Levine, the lead researcher, told the BBC if the trend continued humans would become extinct.

“If we will not change the ways that we are living and the environment and the chemicals that we are exposed to, I am very worried about what will happen in the future. Eventually we may have a problem with reproduction in general and it may be the extinction of the human species.”

Among the many end-of-the-world stories we like to tell ourselves, the infertility apocalypse is the least violent and the most interesting. But the sperm crisis really isn’t here yet, or even looming on the horizon.

This big review of the existing research did no new work, but it did extract more reliable data from the many studies conducted by other groups and there is something going on. Compared with 1970s, sperm counts now in the predominantly white developed countries (North America, Europe, Australia and New Zealand) are between 50% and 60% down now.

It has been a fairly steady decline, and and it is continuing, but no such fall has been found in the sperm counts in South America, Africa and Asia. So maybe it’s just whites going extinct.

Probably not, though. Most people in South America are white, but there has been no fall there. And there’s no separate data in the survey about what’s happening in the heavily industrialised Asian consumer societies like Japan, Korea, China and Taiwan, but one suspects that there have been declines there. It’s almost certainly an environmental, dietary or lifestyle effect, and therefore probably reversible.

There’s no immediate cause for panic, because all of the studies showed that sperm counts, though lower than in the 1970s in some parts of the world, are not “sub-fertile” anywhere. They are still well within the normal range, just lower on average. There’s no shortage of human beings at present, and there’s lots of time to sort this out.

It will almost certainly turn out, when more research has been done, that the main cause is the presence of various man-made chemicals in the environment, a cocktail of that imposes a burden on the normal functioning of human metabolism.

We are breathing and ingesting a lot of toxins and have been since shortly after the rise of civilisation (lead-lined water pipes, etc). The sheer volume of visible pollutants (particulate matter, etc) has probably peaked and begun to decline in the most developed countries, but the variety of new chemicals in the environment continues to rise.

Unfortunately, that’s the way human beings work: ignore the problem or put up with it until it becomes unbearable, and only then do something. It’s a strategy that has served us well, but will do us increasing damage as the problems become more complex. It’s unlikely, however, that falling sperm counts will be the one that finally gets us.

Dyer is an independent journalist whose articles are published in 45 countries.