My Sperm is Fine – The Myth of Endocrine Disruption

Originally published on 25 October 2013

Twenty years ago, a literature review published by Niels Skakkebaek et al concluded that there was a serious decline in male sperm count levels, predicting a doomsday scenario and suggesting that this “crisis” was due to environmental factors (synthetic endocrine disrupting chemicals or EDCs). This publication sparked controversy in part because the review used publications dating back to the 1930s when the technology for sperm counting was, well, as rudimentary as slide rulers. Since this publication, the scientific community was split on whether endocrine disruption was occurring (were sperm counts actually declining) and what was causing it (were synthetic chemicals to blame, or, as the Risk-Monger likes to postulate, did this decline coincide with the recent dramatic increase of soybeans, rich in endocrine disrupting isoflavonoids, being added to our processed foods?).

Since then, more funding was made available for scientists to perform more studies, so as long as doubt prevailed and the need for further studies persisted, many researchers were quite happy. For the environmental activists, this was manna from heaven – they could wield the sword of endocrine in their campaigns against chemicals, plastics, pesticides (the emotional uncertainty of what was going on with my kit would certainly draw regulatory attention). There is even a campaign against chewing gum as an endocrine disrupter (I suppose it must be run by school teachers!). A second generation of researchers completed their studies, under the tutelage of activist scientists like Andreas Kortenkamp or Niels Skakkebaek, learning to not trust industry researchers or government scientists (see the common thread in the affiliations of the signatories of the activist driven Berlaymont Declaration).

Semper fidelis

As the scientific evidence was far from certain, from 1996, the Danish government engaged Skakkebaek and his team to conduct a large-scale longitudinal research of young Danish men (around the age of 18 and thus at the peak of their sexual prowess) entering the military from two Danish cities. More than 5000 sperm and blood samples were taken, questionnaires were filled out and data analysed over 16 years. Using the best analytical technology available, the most reliable methodology from the largest sample range ever over an extended time period, the hope was that we could know, once and for all, whether endocrine disruption was occurring, and what was behind this phenomenon. It allowed Skakkebaek to prove his theory which had led to twenty years of robust scientific and regulatory debate.

How did activist researchers cheat the evidence on endocrine disrupters?

The scientific community patiently waited for Skakkebaek to release his data – data that would inform the debate and remove doubt once and for all about the state of play regarding our risks from synthetic chemicals (or, more likely, the increased soy in our diet). And they waited some more, but still no data was released. Sixteen years of funding and access provided by the Danish government for scientists to conduct state of the art research and there was only silence. A representative from the Danish National Board of Health, within his right as the research funder, finally demanded access to the data, and upon receiving it, did what any responsible civil servant would do with work funded with public money: he released the data on-line to the public.

It should not come as any surprise that the data from 16 years of comprehensive sampling of the most relevant male cohort showed that there was no evidence of any decline in sperm counts from the thousands of samples taken. Curiously, sperm counts were increasing quite significantly in the last four years before the sampling stopped (see table).

Other scientists examined this data and found it vitally important for the debate. Jens Peter Bonde et al published a commentary in Epidemiology (22:5, 2011, p 617-619) entitled Trends in Sperm Counts: The Saga Continues. The commentary cites much more plausible causes for earlier declines in sperm counts in Danish men (women drinking and smoking during pregnancy shortly after WWII). The article puts Skakkebaek et al in their place by concluding:

In searching for possible etiologies of reproductive disorders, we need to pay attention not just to environmental toxicants, but to the wide range of behavioral, medical, and other factors that have potential to damage human reproduction.


Source: Jens Peter Bonde et al, Trends in Sperm Counts: The Saga Continues, Epidemiology 22:5, 2011, p 618.

So the best scientific data (under the best conditions, cohort, methodology and duration) shows that there is no decline in sperm counts. One would expect that this would “disrupt” the activist researchers’ campaign activities. Instead, they lashed out at those who dared to interpret the data they attempted to not release. I wish I were joking, but with hostile rage, Skakkebaek et al retorted, in the same journal:

Is it good scientific practice to publish other researchers’ data without permission before these data have appeared in a peer-reviewed scientific journal? Is it good scientific practice to cite newspapers as a source of truth in scientific articles or to claim that other researchers have withheld data—without providing any kind of evidence for such a claim? Is it good practice for an editor of a scientific journal, in collaboration with an invited scientist, to publish editorials that contain serious and misleading accusations against another group of scientists without giving that group a chance to tell their side of the story?
Source: Skakkebaek et al, Sperm Counts, Data Responsibility, and Good Scientific Practice, Epidemiology 22:5, 2011, p 620

Well, Dr Skakkebaek, is it good scientific practice to withhold data that the public has paid for because it does not support your political views? This is indicative of a narrow-minded generation of activist scientists who fail to recognise that when the public funds them to do research, they are themselves serving the public interest and not their own. Public ethics and not personal egos or ideology must be applied. By the way, to the best of my knowledge, they never did tell their story!

The mainstream scientific community is fed up with these activists. The tone of the commentary published by JP Bonde et al (referenced above) is almost snickering. Less amused are the 81 high-level endocrinologists and toxicologists who signed the letter sent to Anne Glover, begging the EU to respect proper scientific procedure on regulating EDCs. The regulators in DG Environment do not appear to be listening.

Skakkebaek and members of his team did not sign the letter to Anne Glover. Instead, the EDC activist researchers are pushing for precaution on plastics, pesticides, and well, why not, chewing gum (Skakkebaek signed the activist driven Berlaymont Declaration instead). Even with bad science, their campaigning will probably succeed because the precautionary principle is bent in their favour.

The Risk-Monger himself was quite surprised to see these results as he had assumed that sperm counts were indeed declining. Not from chemicals and that silly activist campaign nonsense, but from the near sterilising level of exposure to soy beans that western societies have exposed their food-chain to over the last 50 years (found in up to 60% of our processed foods – see an earlier blog). Unless young Danish men are serious red meat eaters, the high levels of exposure to endocrine disrupters from consuming soy (as well as coffee and other legumes) would seem to confirm the theory that the human endocrine system is highly adaptive to outside influences. More research into human resilience should be funded, instead of imposing stupid regulations based on bad activist science.

Scientific dis-integrity

The man on the street may consider all scientists as objective, knowledgeable people in white coats whose mild, demure and bookish nature borders on grandpa-ish kindness. The man on the street has never attended faculty meetings or fallen prey to their political agenda at conferences where activist scientists can become very “unscientific”.

Typical academic faculty meeting

My experience is that such academic big egos exhibited by these activist scientists are much like packs of hyenas – they don’t really care whose flesh they rip into, as long as it is not their own (or their mercenary post-docs). For such characters, the moral choice between admitting being mistaken for the last twenty years versus continued funding for their fallacies to build their legacy for the next twenty is a no-brainer.

Why did Skakkebaek not publish his data and only release it under pressure from the Danish government? Why did he publish a paper on Finnish data from a much smaller sample range and weaker methodology (that showed a decline in sperm counts) and not bring in his contradicting Danish data? In the article referenced above, Skakkebaek claims that the journal editor asked him to remove the Danish data but my experience with journal editors is that they would not run from juicy scientific contradiction. I will leave these questions to Skakkebaek’s conscience.

Fear and Funding

This is what we do know. Funding in the EU for EDC research has been slowly drying up (following the end of the FP6 CASCADE network of excellence programme and a cornucopia of national research projects) just at the time as the next generation of anti-chemicals researchers have finished their PhDs (under the tutelage of the above-mentioned activist researchers) and are now scrambling for post-doctorate peanuts. Without controversy and political imperative, those funds would not be forthcoming. In other words, the facts have to match the need for fear.

But the facts from the best available research show we should not be afraid (and that we should get over this political activism and move on). Still, the regulators in DG Environment and certain MEPs continue to cry their hormonal wolf. They are egged on by new NGO anti-chemicals umbrella groups like EDC-Free Europe (also seeking more EU funding to lobby themselves).

This has been a cute game played by interest groups and activists over the last two decades, but it is time for it to stop. Their motives are compromised, their science is tainted and their reputations are in shambles.

It is also time for our decision-makers to show some balls and stand up to these activists and their tactical games. It is quite alright for them to do this. Recently released and very reliable data from Skakkebaek et al can reassure EU regulators that they still have their manhood.

Addendum June, 2016: Since writing this blog in 2013, Skakkebaek has still, to the best of my knowledge, not published his analysis on the Danish study findings. However I found another recent Skakkebaek ten-year study on evolutions of Finnish sperm samples of men during the ages from 19 to 29. Again his team had found an increase in sperm levels and motility, forcing Skakkebaek to criticise the methodological limitations of his own study. Priceless!

Front image source

6 Comments Add yours

  1. AlainCo says:

    This is sadly a no news.

    Note that in indonesia it is known that Soya is good for lactating mother.
    It is also known that Ananas core is evil for pregnant women (dunno why… toxic product?).

    naivety of modern urban environmentalist about nature would make many older people laughing.


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