Summary: Another front in the decline of men — falling sperm counts. Remember, Romans knew that lead was toxic. They just did not bother to worry about it. So just read the news and think about what you are told to think about.
“Spermageddon: Why the human race could be infertile in 50 years“
By India Sturgis in The Telegraph, 27 January 2018.
“Stefan Chmelik, an integrated healthcare practitioner and the founder of Harley Street’s New Medicine Group, is quite clear in his predictions. ‘There are scant mainstream medical treatments for male fertility and, at current rates of sperm decline, the human race will be infertile in 50 years. I’m beginning to see IVF babies of IVF babies.’”
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“Sperm counts, testicular cancers, and the environment.“
By Niels E Skakkebaek (bio here).
Editorial in The BMJ (formerly the British Medical Journal), 10 October 2017.
Gated. Open copy here.
Disturbing trends in men’s reproductive health demand urgent attention.
A recent meta-analysis by Levine and colleagues showing significant declines in sperm counts among men in the Western world caught considerable media attention. The Levine study followed a similar report in The BMJ 25 years ago. Should we be concerned? Is male reproductive health really at risk?
Meta-analyses have some inherent limitations. However, an important and often overlooked point about data on the quality of semen is that trend data should be interpreted with a holistic view of male reproductive health problems, including parallel trends in testicular germ cell cancer (TGCC). Incidence of this cancer has risen substantially over the past few decades, particularly in young men. Increases seem to be occurring even in countries that have had low incidence. …
Environmental influences.
What could be causing such disturbing trends? The short answer is that we do not know. However, data suggesting that the incidence of testicular cancer has more than doubled in recent decades leaves little doubt that we should look into environmental causes — including lifestyle effects. Alterations in our genome cannot explain the observations as changes have occurred over just a couple of generations.
Environmental exposures can come through food, water, skin, and work and home environments. Both wildlife research and experimental studies suggest that modern lifestyles are associated with increased exposure to various endocrine disrupting chemicals such as pesticides that together may be harmful to wildlife and humans even though exposure to individual chemicals is low. However, little has been done to explore their potential effects on semen quality and testicular cancer. In particular, studies of maternal exposures in pregnancy and the subsequent reproductive function of their sons are needed.
Should we be worried about our future ability to reproduce ourselves, as some media coverage has claimed? This inconvenient question makes sense when we look at what is going on in fertility clinics all over the world — more and more children are now born after in vitro fertilisation, intracytoplasmic sperm injection, and insemination with partner or donor sperm. …
In order to help future generations we must act now to prioritise new basic and clinical research programmes in reproductive medicine. Simple research questions urgently need answers. What is the role of exposure to endocrine disrupting chemicals in reproductive trends? What is the role of lifestyle factors, including recreational drugs? What is the role of dysgenesis of fetal testis caused by maternal exposures? Why is the incidence of testicular cancer increasing among young men of reproductive age?
Medical researchers cannot do it alone. We need health and research authorities that can see the urgent need for research in reproductive medicine, not just more infertility treatments, which are a short term solution for individuals not for the fertility of future generations. It’s even possible that the use of intracytoplasmic sperm injection to overcome poor semen quality may be producing new generations with poor reproductive health.
We have already waited too long. As New York Times columnist Nicholas Kristof recently wrote: “Our human future will only be as healthy as our sperm.”
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Now for some research.
“Evidence for decreasing quality of semen during past 50 years.“
By E. Carlsen et al. in The BMJ, 12 September 1992.
OBJECTIVE — To investigate whether semen quality has changed during the past 50 years. …
SUBJECTS — 14,947 men included in a total of 61 papers published between 1938 and 1991. …
RESULTS — Linear regression of data weighted by number of men in each study showed a significant decrease in mean sperm count from 113 x 10(6)/ml in 1940 to 66 x 10(6)/ml in 1990 (p < 0.0001) and in seminal volume from 3.40 ml to 2.75 ml (p = 0.027), indicating an even more pronounced decrease in sperm production than expressed by the decline in sperm density.
CONCLUSIONS — There has been a genuine decline in semen quality over the past 50 years. As male fertility is to some extent correlated with sperm count the results may reflect an overall reduction in male fertility. The biological significance of these changes is emphasised by a concomitant increase in the incidence of genitourinary abnormalities such as testicular cancer and possibly also cryptorchidism and hypospadias, suggesting a growing impact of factors with serious effects on male gonadal function.
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“A Population-Level Decline in Serum Testosterone Levels in American Men“
By Thomas G. Travison et al. in The Journal of Clinical Endocrinology & Metabolism, 1 January 2007.
Context — Age-specific estimates of mean testosterone (T) concentrations appear to vary by year of observation and by birth cohort, and estimates of longitudinal declines in T typically outstrip cross-sectional decreases. These observations motivate a hypothesis of a population-level decrease in T over calendar time, independent of chronological aging.
Objective — The goal of this study was to establish the magnitude of population-level changes in serum T concentrations and the degree to which they are explained by secular changes in relative weight and other factors.
Design — We describe a prospective cohort study of health and endocrine functioning in randomly selected men of age 45–79 yr. We provide three data collection waves: baseline (T1: 1987–1999) and two follow-ups (T2: 1995–1997, T3: 2002–2004). This was an observational study of randomly selected men residing in greater Boston, Massachusetts. …
Results — We observe a substantial age-independent decline in T that does not appear to be attributable to observed changes in explanatory factors, including health and lifestyle characteristics such as smoking and obesity. The estimated population-level declines are greater in magnitude than the cross-sectional declines in T typically associated with age.
Conclusions — These results indicate that recent years have seen a substantial, and as yet unrecognized, age-independent population-level decrease in T in American men, potentially attributable to birth cohort differences or to health or environmental effects not captured in observed data.
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Temporal trends in sperm count:
a systematic review and meta-regression analysis.“
By Hagai Levine et al. in Human Reproduction Update, Nov-Dec 2017. Gated.
Sperm concentration: SC. Total sperm count: TSC.
BACKGROUND — Reported declines in sperm counts remain controversial today and recent trends are unknown. A definitive meta-analysis is critical given the predictive value of sperm count for fertility, morbidity and mortality. …
OUTCOMES — SC declined significantly between 1973 and 2011 …the mean SC declined, on average, 1.4% per year with an overall decline of 52.4% between 1973 and 2011. Trends for TSC and SC were similar, with a steep decline …of 1.6% per year and overall decline of 59.3%. …
WIDER IMPLICATIONS — This comprehensive meta-regression analysis reports a significant decline in sperm counts (as measured by SC and TSC) between 1973 and 2011, driven by a 50–60% decline among men unselected by fertility from North America, Europe, Australia and New Zealand. Because of the significant public health implications of these results, research on the causes of this continuing decline is urgently needed.
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“Male fertility: hard facts vs flaccid myths“
By Rob Kemp in The Telegraph., 26 July 2017.
“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,” the lead researcher, Dr Hagai Levine, said. “Eventually we may have a problem, and with reproduction in general, and it may be the extinction of the human species.” …
In 2015, I spoke to Paul Serhal, male fertility consultant and Medical Director of the London-based Centre for Reproductive and Genetic Health, about why he thinks such “scare stories” surrounding sperm health are a distraction from the real causes for concern.
Myth: Chemicals kill male fertility.
“Although there are issues over the influence of plastics and chemicals on health and wellbeing, this study linking plastics compounds and sunscreen chemicals directly to low sperm count is far from conclusive,” Serhal argues. “None of these elements are likely to be the root cause of problems for couples desperate to conceive.”
Instead, Serhal insists that such factors as age, diet, bad habits such as smoking and carrying excess weight are much more likely to hamper the potency of a man’s sperm. “Having an egg for breakfast in a non-stick pan, protecting your skin with factor 20 or driving a car with new upholstery – none of them is a realistic risk to sperm quality.” …
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Some research comes to other conclusions
“Declining Worldwide Sperm Counts: Disproving a Myth” by Harry Fisch in the Urologic Clinics of North America, May 2008. Gated; open copy here.
“Human semen quality in the new millennium: a prospective cross-sectional population-based study of 4867 men” by Niels Jørgensen in BMJ Open, January 2012. “This large prospective study of semen quality among young {Danish} men of the general population showed an increasing trend in sperm concentration and total sperm count. ”
For More Information
Also see this post about the effect of Xenoestrogens. hormone-disrupting or so-called ‘gender-bending’ chemicals in the environment, and the implications for human health. Also see Martin van Creveld’s provocative book Pussycats: Why the Rest Keeps Beating the West
If you liked this post, like us on Facebook and follow us on Twitter. See all posts about women and gender roles, especially these…
- Xenoestrogens: a shockwave – a hidden danger.
- The Economist proclaims that men are “The Weaker Sex”.
- Women are moving on top of men in America.
- We might become a low testosterone America. More research needed, stat!
- Women on Top, chapter 10: the growing gender gap in education.
- Victims no more: the revolution puts women on top of men.
A look at America’s future.
Low testosterone levels are linked to low sperm counts. To see where America is going look at this test of the four men from “The Try Guys” on Buzzfeed. Assuming they accurately reported the results…
“The normal T-score for an adult male ranges from 270-1,070 ng/dL, with men aged from 25-34 averaging out at 617 ng/dL. Not one BuzzFeed beta male met the 617 ng/dL average; rather, all the men testing below the level of a typical 85-year-old male (376 ng/dL). Moreover, three of the four men tested below the average range, and the male with the highest testosterone level, Eugene, still had a relatively low T-score with 363 ng/dL.” {From the Daily Wire.}
Buzzfeed Betas’ T-levels
Average male T-levels by age.
“The Try Guys”, episode 13 in season 9.
I couldn’t tell from the studies – do any of them correlate with weight?
One other thought that’s occurred to me on this broad topic is that some areas of the world had populations where there was a place for men to go and not be expected to have families, but this has changed relatively recently. (Or the institutions have not grown to keep up with the “demand” for celibacy, so to speak.)
SF,
Obesity is often mentioned as a likely cause, as in Kemp’s Telegraph article. But see this from the conclusions of Travison (2017):
“where there was a place for men to go and not be expected to have families,where there was a place for men to go and not be expected to have families,”
Women, also (e.g., nuns). More broadly, in many times and place a large fraction of men and women were unmarried — and (to a lesser extent) celibate. It was part of the hierarchical structure of society.
Are low T, low sperm counts, and higher incidences male transgenderism related? Is it likely we’re facing a massive public health crisis that we can’t address because of our ideologies?
Corporate Lawyer,
“Are low T, low sperm counts, and higher incidences male transgenderism related?”
Now that is an interesting thought! Here is another: perhaps low-T and low sperm levels have produced generations with more beta men — and feminism is a reaction to that.
“Is it likely we’re facing a massive public health crisis that we can’t address because of our ideologies?”
Problem identification is often the most difficult step in the process. Many of our problems have powerful special interest groups with political and/or financial interests in getting attention for “their” issue. This makes it difficult to have a rational response to our full spectrum of risks.
Too much time sitting down, not enough exercise (particularly hard physical exercise), too much fat, drinking too much, smoking and other drug use.
I’ve also wondered about the sort of underwear blokes wear. Sperm production is temperature sensitive, perhaps we should all be going commando rather than wearing budgie smugglers.
Finally, is it possible that there are epigenetic effects (assuming that epigenetics exists)? A nice present handed down to us from our parents and grandparents who all smoked.
I eagerly await the blockbuster paper linking declining sperm counts to climate change…
Steve,
I suggest relying on research rather than folk wisdom. Premature conclusions do more harm than good.
These factors are discussed in these reports. Note the conclusion that the causes of this are not well understood, such as this in Travision 2017:
Research is needed, but the conclusions may be too socially and politically explosive to publish. One obvious candidate for environmental factors contributing to widespread low-T is the lingering presence of birth-control hormones measured in metropolitan water supplies.
Craig,
Fortunately, the physical sciences are not as corrupt as the social sciences. There is quite a bit of research about xenoestrogens (aka endocrine disruptors). Here is a 2009 post about it; much has been done since. I have not followed it, so I don’t know the current findings.
Thanks for the reminder. I’ll look at the subject. (Also, I forgot to thank you for posting the link to the great SNL sketch about sexual harassment.)
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