FERTILITY RATES: Why, without massive change, the human race will be extinct by, at the latest, 2250

ARE BOXES LIKE THIS SET  TO WIPE OUT OUR SPECIES? IS MODERN LIFE DOOMING US TO EXTINCTION?

50% drop in human sperm counts since 1945

75% of men set to be infertile within 30 years

Here are some not entirely random facts to ponder of a Sunday morning:

1. Experts who gathered in London for the European Society of Human Reproduction and Embryology annual conference in July 2013 spent the entire day debating what some are calling ‘the human male fertility crisis’. A long-term monitoring analysis conducted by France from 1989-2005 found the sperm concentration of men had decreased by nearly one-third. That really is rather a lot.

2. Alongside that, an apparently well-conducted study from the 1990s suggested sperm counts in ‘the West’ have decreased by half since the end of the Second World War. That too is a big number.

3. Since then, a major coordinated study across Northern Europe has found that as many as 1 in 5 young men have sperm counts low enough to affect fertility – according to Richard Sharpe, a male reproductive health specialist at the University of Edinburgh.

As with any left-field development, the field is rife with argument, counter-argument, endless web pages devoted to dozens of potential causalities, and the classic prophet vs denialist spectrum. But more and more scientists studying the phenomenon are convinced that – while they may argue about the cause – male sperm counts are falling.

We don’t know if this differs by nation, continent, culture or indeed anything else of very much importance: it hasn’t been studied much in Asia – and almost nothing is known about South America or Africa. All we can say (and it’s pretty feeble) is that the average chap produces upward of 60 million sperm per millilitre of semen, and has little problem impregnating the missus if he’s churning out 40 million per ml. But under roughly 20 million per ml, they’ll be considered ‘subfertile’….a sort of reproductive equivalent of toxic auto-loans – only, with much greater ramifications.

So to pause for thought at this point, here’s an extrapolation:

A decrease by 50% over 50 years means – given we don’t know the rates of decline involved – that some 350 million men in the West may be experiencing problems having kids…but their fathers weren’t.

Now, before we all get over-excited and abusive at the comment thread, let me just stress that there are more unknowns in all this than you’d find at a lonely people’s convention. But some speculation must surely be allowed:

1.The standing assumption for over forty years now in the West has been that people are having fewer children because greater material wealth/female liberation means they choose so to do. What if 50% of those data are actually recording an outcome that was based on unexplained infertility rather than lifestyle choice?

It’s possible that this may partly explain the increase in IVF usage, but personally I doubt it: although – as with most emotionally important procedures – availability itself immediately stimulates usage, nearly forty years on its usage rate is still only 236 IVF cycles per 100,000 pregnancies. What we don’t know, however, is how many IVF procedures involve careful taking of ‘straws’ from the male scrotal sac when low male fertility is the problem.

More likely, I think, is that lifestyle decisions land many couples with a problem, because fertility decreases with age…which takes us back to the point above.

2. Is natural selection in play here? More specifically, is the human race undergoing a creeping cull but we just haven’t noticed yet?

Nobody can answer that with any certainty as yet, but it’s an intriguing thought. As I say, the potential external ‘ecological’ culprits range from pesticides all the way up to God.The pesticide thing I find difficult to credit, because France has seen one of the biggest drops in their use over the last thirty years…but an alarming drop in fertility over roughly the same period. As for God, well – she was too busy to talk to me. But as we know, she moves in mysterious ways.

A more likely culprit than pesticides is bisphenol-A (BPA) – found in hard plastic items like food containers – which may well produce count falls because it’s an oestrogen-like “endocrine disruptor.” Three years ago, researchers at the Harvard and Michigan Schools of Public Heath, reported a strong relationship between BPA and sperm counts – men with the highest levels of BPA in their urine had 23% lower counts than those with the lowest exposure to BPA. (The study has since been repeated in China, and produced very similar results among packers in a Chinese factory).

Here too, though, I have a problem: BPA first became widely available in the mid 1960s. What about the 27 years before that when counts were declining at a similar rate?

To reiterate the obvious: an immediate conclusion one reaches on the male infertility question is that, just as with the climate change bunfight, there are literally thousands of potentially contributory factors to be taken into account. Here’s just one alarming range of research studies upon which we can chew:

Chemical Sample location Reference Cadmium Croatia (Jurasovic 2004) Nigeria (Akinloye 2006) Singapore (Chia 1992) Chromium India (Danadevi, Rozati et al. 2003; Kumar 2005) Copper China (Yuyan, Junqing et al. 2008) DDT South Africa (Aneck-Hahn, Schulenburg et al. 2007) Environmental Ozone Los Angeles, USA (Sokol, Kraft et al. 2006) Glycol ethers Paris  (Multigner, Ben Brik et al. 2007) UK (Cherry, Moore et al. 2008) Lead Arequipa, Peru (Eibensteiner 2005) Northern Mexico (Hernandez-Ochoa 2005) Manganese Nigeria (Adejuwon 1996) Molybdenum Michigan, USA (Meeker, Rossano et al. 2008) Nickel India (Danadevi, Rozati et al. 2003) Organochlorine pollutants Ukraine, Poland, Greenland* (Toft, Pedersen et al. 2004; Toft, Rignell-Hydbom et al. 2006) Organophosphate pesticides China (Padungtod, Savitz et al. 2000) Southern Mexico (Perez-Herrera, Polanco-Minaya et al. 2008) Phthalate platicizers Lucknow, India (Pant, Shukla et al. 2008) Shanghai, China (Zhang, Zheng et al. 2006) Pyrethroid insectides China (Xia, Han et al. 2008) Styrene Denmark  (Kolstad 1999) Zinc China  (Yuyan, Junqing et al. 2008)

The ‘dustbin diagnosis’ looking at this would be ‘modern life is reducing male fertility’. And I suspect in some instances it is. But the syndrome has been around since the 1930s. And some of the correlations with high sperm count are, to say the least of it, contradictory. For instance, “giving a man testosterone is an effective form of birth control” says one leading US male infertility expert. But “If testosterone is lowered during adulthood, a man may be unable to have children” says the Mayo Clinic. “Opinions,” George Burns once remarked, “are like assholes: everyone’s got one”.

Perhaps the key question to ask is, “Do experts in the field know if falling male fertility is progressive?” Or more exactly, is the incidence of it (a) broadening and/or (b) showing an acceleration in amount of decline per victim?

In April 2011, the European Science Foundation published a study openly stating that ‘sperm counts and sperm quality have been dropping consistently in the developed world for the last 50 years’. The flaw in this, again, is that nobody’s done much work in the 2nd and Third worlds.

Even more potentially significant, perhaps, was the 1992 Danish study reporting that counts ‘have dropped by 1% every year since 1938′. That too suggests a steady decrease over time. But other studies mentioned earlier suggest a compound decline effect….and even a ‘steady’ drop will produce compound decline by the time is hits the next male generation.

So, falling sperm counts are progressive from one generation to the next.. Oh dear. Or ‘O joy’ – depending on your view of population control.

Thus, although I initially felt the data didn’t add up – seventy years after the first conclusive study, we should all be infertile – this is because the inter-generational compound effect is real.

While the ‘average’ density range bulges (sorry) at 30-60mill today, that itself was almost certainly 50-100 mill in 1938. Where it gets more statistically complex is that the full ‘normal’ sperm density count ranges ‘from 15 million to greater than 200 million sperm per milliliter of semen’ according to the Mayo Clinic. …and just to be awkward,  Resolve.org says it’s 40-300 million.

So what we have at the moment is an open-ended universe of variety and conflicting views….and that makes any further certainty impossible: the only hard (sorry) data I can find says that 1 in 5 blokes have a sperm count either side of the 30-60 average. Although a report quoted in the Sunday Express this morning records ‘the worrying trend in male infertility, which affects one in four men’.

Despite all those caveats, three years ago the director of Rochester Center for Reproductive Epidemiology Shanna Swan  – while conceding that “it’s hard to know for sure” – put the yearly sperm drop at 1.5% in the U.S., and 3% percent in Europe and Australia. So setting aside the exact cause, clearly something important is going on…and different Sovereign States are reacting in a variety of ways.

For Japan and China, the loss of replacement babies now means a serious problem of demographic skew towards the aged: but yet again, we don’t know how much of that is choice, and how much male infertility.

Last month, reports from Turkey showed the military highlighting an embarrassing problem: the Kurds that Erdogan feels somewhat equivocal about produce more children than other Turkish citizens. The General Staff have told Erdo that within half a century the vast majority of army call-up recruits will be Kurdish. But in Turkey as a whole, sperm counts are falling: a 2005 study suggested that exposure to chromium might be an issue – but yet again, the studies have been sporadic.

Confused? Join the club. But even at the end of this morass of opinion, findings and interpretation, I still believe there are some certainties involved: and they aren’t pleasant.

* 1938-1992 decline from 50-100 range to 30-60 range = 25% loss per generation. Even with a minimal compound effect, the range by 2019 is going to be 22-45, by 2046 15-30 and so on. On that basis, thirty years from now roughly three-quarters of all men will be potentially infertile.

* By 2100, probably 9 in 10 men will need medical assistance in order to reproduce.

* Eventually, the DNA base will be too small for healthy species survival. Without external changes, we will be extinct (at current longevity rates) before 2250.

* These methods are bound to present themselves: cloning, artificial semen impregnation, elimination of all harmful chemicals known to have a negative effect on counts, massive semen storage via those men with high sperm counts.

* Mating with another species is a distinct probability. Some geneticists both in the UK and the US believe that without this, further human evolution cannot occur anyway.

This may not make for a Brave New World; but it will make for a world in which rather more bravery than now is a table stake for every remaining member of Homo sapiens.

Enjoy your lunch.

Last night at The Slog: when calm debate spirals down into hate-slinging

Filed under: MALE HUMAN FERTILITY CRISIS POINTS TO CERTAIN EXTINCTION Tagged: By 2100 90% of human males will be infertile, Humans extinct by 2250, Male sperm counts halved in 50 years