Falling Sperm and Testosterone in Men


Sperm counts worldwide are plummeting faster than we thought

 
Five years ago when we set off on this journey to create Naître, there was a landmark study released that described the decline in sperm counts, sparking widespread concerns that humanity was on the path to extinction. Now a new study shows that sperm counts have fallen even further and the rate of decline is actually speeding up, raising fears of a looming global fertility crisis.


The initial study, published in July 2017 studied men in North America, Europe, Australia, and New Zealand between 1973 and 2011 and revealed that sperm counts had plummeted by more than 50%. The same research team set out to discover what had happened in the last 10 years to add to that data. This time they explored a more global perspective and involved semen samples from 14,233 men, including some from South and Central America, Africa, and Asia. The upshot: Not only has the decline in total sperm counts continued—reaching a drop of 62 percent—but the decline per year has doubled since 2000.


“The decline is not tapering off—it’s steep and significant,” says study co-author Shanna Swan, a reproductive and environmental epidemiologist at the Icahn School of Medicine at Mount Sinai in New York City. “Overall the drop is similar in magnitude but when we look at recent years, we see that it’s speeding up.”




Study lead author Hagai Levine, a medical epidemiologist at Hebrew University of Jerusalem’s Hadassah Braun School of Public Health, calls the results “worrisome as we were hoping that at some point the decline would be levelling off. The opposite may be true, and we may cross a tipping point when most men will be sub-fertile or when the causes of this decline will also manifest by other adverse health trends.”
 
“We may cross a tipping point when most men will be sub-fertile,” 

This is important as we are seeing rising infertility and contrary to common perception, infertility impacts men and women equally. I think the misconception that infertility is primarily a woman's problem is due to the tendency for women to seek medical help or have a regular relationship with their GP or health practitioner. Men on the other hand may not be as proactive in regards to their reproductive health. 


This new data shows that an increasing number of men are showing low sperm counts that will reduce their capacity to fertilise their partners. This is not only a concern for them and their families but also society in general as many western countries are seeing shrinking and ageing populations.


Beyond reproductive matters reduced sperm count can also be an indicator of wider health issues as there is an association between semen quality and overall health.

“One can view the decline in sperm counts as a biomarker for male health in general,” says David M. Kristensen, a molecular toxicologist at Roskilde University and Copenhagen University Hospital in Denmark who was not involved in the study.

The study also shows a decline in testosterone levels which are essential for sperm production as well as the testes’ ability to regulate temperature to ensure healthy sperm.
 
“One can view the decline in sperm counts as a biomarker for male health in general,”


What’s also lesser known is that it’s not just the elements that man is exposed to during his lifetime that can affect the quality of his sperm. An expecting mother can also have a permanent effect on sperm quality during pregnancy in what’s known as the “reproductive programming window”. Exposure to environmental chemicals can affect sperm concentrations.


By contrast though, the damage done to a man’s sperm during his life through poor diet,  smoking, exposure to environmental toxins or harmful chemicals is actually reversible. Sperm takes around 75 days to mature so lifestyle changes and detoxifying can give men a new chance of healthy sperm every 2 and half months.


To combat the decline in sperm health we need to understand what the cause is.

 
Both studies didn’t explore the causation but there is a lot of recent research that points to environmental and lifestyle factors that may be to blame. These include exposure to endocrine-disrupting chemicals (which mimic or interfere with the body’s hormones), smoking, and obesity. For example, a study in a 2022 issue of the journal Toxicology found that occupational exposure to pesticides was associated with sperm found in lower concentrations, sperm that were poor swimmers, and sperm with more DNA damage. And a study in a 2019 issue of the journal Human Reproduction found that men who are overweight tend to have reduced sperm concentration, lower total sperm count, and fewer motile sperm.


More research needs to urgently be done to determine what is crashing global sperm counts but in the meantime men and women can try and protect their reproductive health by consuming a healthy diet, exercising regularly, maintaining a healthy body weight, and avoiding smoking.



We’d also recommend trying to avoid reducing exposure to endocrine-disrupting chemicals by being a savvy consumer.

These chemicals include: phthalates (in plastics and personal-care products such as nail polishes, shampoos, and hair sprays), bisphenol A (in hard plastics, adhesives, and the lining of some food cans), flame retardants (in furniture and carpets), perfluoroalkyl substances (in nonstick cookware and stain-resistant carpets), and pesticides (in plant-based foods and lawn-care products).



5 small steps men could start with that could really help:

  • Avoid storing food in plastic
  • Avoid drinking plastic bottled water
  • Avoid air fresheners
  • Switch to better laundry detergents
  • Reduce ultra-processed food consumption