Are Declining Global Sperm Counts Affecting Male Fertility?

It's well known that eggs from the ovaries are half the piece of the reproduction puzzle. The other half, well, is the sperm. When a sperm cell fertilizes an egg, pregnancy happens, explains Planned Parenthood. However, a recent scientific buzz around a new study is hinting that sperm count is going down globally (via The Guardian), which may affect a lot more than pregnancy rates. Male reproductive health expert, Richard Sharpe, tells The Guardian that "These issues are not just a problem for couples trying to have kids. They are also a huge problem for society in the next 50-odd years, as less and less young people will be around to work and support the increasing bulge of elderly folk." This new 2022 study was published in the journal Human Reproduction Update.

For the review, researchers looked through roughly 3,000 studies published between the years 2014 to 2019 looking for specific semen parameters. After finding 38 studies that met their criteria, the scientists extracted the specific semen data which included the following: the total sperm count, sperm volume, and sperm concentration. These metrics were then combined with previous data (which dates back as early as 1973) and inserted into their research models.

Sperm quality may be to blame

What the scientists detected was a decrease in sperm quality and other aspects of reproductive health, explains Human Reproduction Update. In particular, they found that from 1973 to 2018 the semen concentration from all continents had dropped by 51.6%. When a year-by-year analysis was conducted, the researchers reported a 1.16% decline per year post-1972. This number jumped to a 2.64% decrease per year after 2000.

Additionally, the researchers saw a drop in sperm count. From 1973 to 2019, sperm decreased on average from 104 million to 49 million sperm per milliliter of semen, points out CNN. This sperm count data was collected from 53 countries. Researchers were unable to determine which countries had a faster rate of decline. For reference, healthy sperm count densities should range between 15 million to more than 200 million per milliliter, explains Mayo Clinic.

Lead study author Dr. Hagai Levine expresses to The Guardian that the decline clearly demonstrates a decrease in the population's ability to reproduce. But it also may hint at something. "There is a strong link between a man's reproductive health and his overall health. So it could also speak to that too, that maybe we're not as healthy as we once were," says urologist, Dr. Michael Eisenberg, to CNN. Researchers are still unclear of why this trend is happening, but according to The Guardian, some experts believe that environmental and lifestyle factors may be to blame.