Sperm counts are declining around the world, which could reflect a global crisis with broad implications for the survival of the human species.

This is the stark warning coming out of a new study published in the scientific journal Human Reproduction Update. The study analysed data from 53 countries, and found that between 1973 and 2018, average sperm concentration declined by 1.16% each year, increasing to 2.64% per year post-2000, with an overall reduction of 51.6%. This suggests that average global sperm counts have halved in just under 50 years.

Sperm count is not only an indicator of human fertility; it also is an indicator of men’s health, with low levels being associated with increased risk of chronic disease, testicular cancer and a decreased lifespan.

The study builds on the results of an earlier study by the same team in 2017, which showed a decline in sperm counts in North America, Europe, and Australia, with data collected between 1973 – 2011. This new study analysed sperm count from six continents, with a focus on sperm count trends from men in South and Central America, Asia and Africa, which were not reviewed previously, an extra seven years of data collection up to 2018 was also included.

While this study did not examine causes of sperm decline, studies have suggested that exposure to certain endocrine disrupting chemicals can have adverse effects on sperm quality. Studies of male animals have shown chemicals that block the male hormone testosterone, such as certain phthalates, may cause low sperm counts. Professor Hagai Levine, the lead author to this study, said: “Our findings serve as a canary in a coal mine.  We have a serious problem on our hands that, if not mitigated, could threaten [hu]mankind’s survival. We urgently call for global action to promoted healthier environments for all species and reduce exposures and behaviours that threaten our reproductive health.”

CHEM Trust is calling for the UK Government and EU institutions to address hazardous chemicals, including endocrine disrupting chemicals. In the meantime, there are actions to take to reduce your risk of exposure to hazardous chemicals. For more information see our website.

Read our interview with one of the co-authors of the study Dr Shanna Swann about her research on chemicals, fertility and reproductive health