Gwynne Dyer: A shortage of sperm

Many years ago, when I was young and handsome, a friend inveigled me into taking a small role in a film he was making— a proper film, with a real budget and a commercial release, though mercifully it never got much attention. It was a Cold War spoof called The Last Straw in which the Soviets were plotting to bring the West to its knees by causing the sperm count in Western males to collapse, and I got the Dr. Strangelove role.

This friend— let’s call him Giles Walker, because that was his name— picked me for the role because at the time I was known for making weighty prognostications on the strategic balance and matters pertaining thereto. (You have to make a living.) So I played myself, briefing the leaders of the Free World on the appalling strategic consequences if the Soviet plot succeeded.

You cannot even find this film on YouTube now, I’m pleased to report. However, it did give me a head-start on considering the appalling consequences of a drastic fall in the sperm count of Western men. This comes in handy at the moment, since that is now actually happening.

In the 15 years between 1989 and 2005, according to a study just published in the journal Human Reproduction, the sperm count of French men fell by one third. More than 26,000 men were tested in the study, and the number of millions of spermatozoa per millilitre of their semen was falling by almost two percent a year. If that rate of decline has been maintained since the study ended, the count will be down another 13 percent by now.

Now, admittedly, counting sperm is tricky. You can fit a hundred million of the little buggers into a teaspoon, they all look alike, and they keep wriggling around. But these results being taken very seriously because they don’t have the usual defects of this sort of study.

Most studies on sperm counts use data from men who donate sperm for artificial insemination centres (who are chosen for their high fertility), and/or from couples who are having trouble conceiving (which may be due to an abnormally low sperm count in the male partner). In neither case is it a genuinely representative sample.

The virtue of the French study is that the country has the Fivnat database, a record of some 440,000 cases of infertility problems at 126 government-funded “assisted fertilisation centres” from the 1980s onwards. The researchers chose only the 26,200 cases where the problem had proved to be complete sterility in the female partner—which presumably meant that their male partners were a random sample of the population.

Treatment for infertility is free in France, so there should be no income bias in the data either. For those reasons it is probably the most reliable survey of changing sperm counts over time that has ever been done— and it documents a steep fall in a relatively short time.

The numbers are quite impressive: from 73.6 million sperm per millilitre in 1989 to only 49.9 million per millilitre in 2005. If the rate of decline has stayed the same since 2005, the number now would be around 43 million. Doctors generally regard 15 million as the number below which there will be serious problems with fertility, so there’s another 40 years or so before the problem gets really serious. But still...

There are really three questions here. One, is the same thing happening elsewhere? Two, what’s causing it? And three, how much does it matter?

Most other scientific studies in developed countries in the past 20 years have also found falling sperm counts, though none of them matched the French one in scale and precision. There is no comparable research on the trend in developing countries, but it is at least plausible that this may be a global phenomenon.

That mostly depends, of course, on what’s causing it. If it’s environmental factors, are they the same in rich countries and poor ones? A common theory lays the blame on chemicals in the environment like Bisphenol A, found in some plastics, that disrupt endocrine function and change hormonal balances. Another theory blames smoking, drinking alcohol, and high-fat diets. These factors vary from one country to another, and more research is clearly needed.

But let us suppose that the trend is continuing, and that sperm counts are also declining in developing countries. Should you lie awake at night worrying that this is a threat to human survival?

Definitely not. If you’re really worried about keeping human numbers up, then you should be doing something quite different at night. And afterwards, you might lull yourself to sleep pondering whether it would really be such a bad thing if the birth rate dropped for a while.

If this decline in sperm counts is caused by environmental factors, then it can almost certainly be reversed eventually by doing enough research and then eliminating those factors. In the meantime, however, we are passing through the astounding total of seven billion humans beings, on our way to nine or 10 billion.

That’s far too many for this finite planet, and a rapid decline in the birth rate, even to below replacement level, would be a Good Thing.

Comments (13) Add New Comment
Astro
Or maybe it's caused by genetic factors. We don't need more people on the planet, we are getting overcrowded; so Mother Nature is lowering the sperm count to lower the offspring and let us live in a less overcrowded environment.
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Jinho Choi
I agree with Dr Dyer. A decline in human numbers can only be a Good Thing. We as a species are not going anywhere. The best thing to happen to us in the west has been the long term decline in birth rates that has resulted from better education for women. Contraception, abortion, and older first-time mothers have made our lives better. Marriage equality and optional motherhood for young women will only improve the human population outlook.
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Leone
Jinho, abortion is great when you aren't the one aborted. Yes, to preventing conception though (because then we aren't having a debate on abortion to begin with). I'm so tired of hearing about reproductive rights when so little is said about reproductive responsibilities.
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Jinho Choi
Leone, abortion is not great. The decision to terminate a pregancy is always considered and examined thoroughly. This consideration and examination often involves anguish, soul searching, and suffering. A foetus is not a person. Your assertion of reproductive responsibilities indicates a disturbing lack of empathy towards status of women. I infer that you are not a woman of childbearing age.

A woman's choice forms an integral part of human rights. Access to contraception and medically administered abortion is law. The issue of legal abortion was settled decades ago. It is not open to challenge.
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dru
"If you’re really worried about keeping human numbers up, then you should be doing something quite different at night."--lolz!

But seriously, at 7 billion people, it is no secret that the planet is overpopulated. Clearly, we can't manage or control our numbers.
So this whole decline in fertility thing might very well be for the greater good of our species.
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nitroglycol
Astro: I think you misunderstand evolution. Evolution does not plan ahead; if it did, organisms (whether bacteria, rabbits, or humans) would level off rather than peaking and crashing. This is clearly the result of external factors; if this stabilizes our population it's a happy accident.
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Greg
More likely that exposure to BSA is all the estrogen and progestogen in our drinking water. Combined oral contraceptive medications are eventually peed out, and water filtration plants currently do nothing to remove them from our drinking water. It's a simplistic explanation, but sometimes the easiest answers are the correct ones as well.
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Leone
Jinho, you said "The decision to terminate a pregancy is always considered and examined thoroughly. This consideration and examination often involves anguish, soul searching, and suffering." If the fetus is not a person then why the drama? And who says I'm singling out women on reproductive responsibilities? It takes two to tango, both men and women need to realize the repurcussions of their actions. And just because something was legally decided years ago doesn't mean it isn't open to review...slavery was legal once you know.
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Urban Survivor
People who advocate a drop in population should always be the first to step up to relieve their precious Gaia of their burden.

Im sure our "betters" are behind any attempt to decrease what they see as the hoi-polloi.
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Urban Survivor
AND ANOTHER THING....only myopic dullards think we are over-populated. You can still fit the entire worlds population comfortably on P.E.I.

Get in a plane and have a look. Lots and lots and LOTS of room. Just because you live in a crowded city, and are easily aggrivated by your daily commute or by your noisy neighbour, doesnt entitle anyone to pass a judgement of genocide
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Jinho Choi
Leone, are you suggesting, in 2012, that a foetus is a person? Seriously? The anguish, soul searching, and suffering involved in considering and examining the decision to terminate a pregnancy involve the impact of this decision on the woman's quality of life. You wrote "If the fetus is not a person then why the drama?". You display such a lack of empathy with women's reproductive destiny that I doubt you are a woman.
You wrote "both men and women need to realize the repurcussions [sic] of their actions". Are you seriously advocating abstinence as a solution to unwanted pregnancy? In 2012?

You seek to equate the legality of abortion with that of slavery. That is scraping the bottom of the barrel, even for a troll.
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Rabbi Bacon
Urban Survivor - you are the myopic dullard. We are not overpopulated because we are running out of room to stand on the planet. We are overpopulated because we are running out of the amount of space it takes to SUPPORT each person. For each person (who, no matter how obese, takes up about a square meter), they require space to produce food, produce all the goods they need, dispose of their waste (both bodily waste and the waste of things they no longer are using), produce oxygen, filter carbon dioxide, etc. Your simplistic idea that there is "lots of room" because you saw empty space is terrifyingly dangerous. When the food supply, or entire biosphere collapses, then nature will take care of that "genocide" for you. Nobody is saying we should kill off the excess humans, but that the planet is finite (at some point), and we best adjust our reproductive ideas to ensure we don't go to that limit. Only religious fools believe the earth has infinite capacity. Clearly, there is some limit, although we can quibble whether it it 5 billion or 50 billion. You dismissive attitude is terifying.
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McRocket
Less people in the world? Fine with me.
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