Male Fertility: Sperm Becomes Less Sperm-Rich, Study Concludes

Should we be alarmed? Sperm concentrations, a factor in male fertility, have declined markedly across the planet in recent decades, according to a major study published on Tuesday. “Sperm concentrations dropped significantly between 1973 and 2018,” summarize the authors of this study, published in the journal Human Reproduction Update and conducted by collecting about forty preliminary studies.

This publication is of unprecedented scope on the subject, even as it confirms the findings of a previous study by the same group led by Israeli epidemiologist Hagai Levin. This one, published in 2017, has been the subject of several criticisms, in part because its findings only dealt with certain countries belonging to the Western world.

This time, by combining more data, the authors concluded that the downward trend also applies to South America, Asia and Africa. “Moreover, evidence suggests that this global decline has continued at an accelerated pace since the turn of the 21st century,” they write.

Obesity, lack of physical activity and pollution in question

Sperm count is one of the factors affecting male fertility, but not the only one. Their mobility also plays a crucial role that is not measured in this study. Therefore, this does not allow us to conclude that there is a general decline in male fertility, even if it gives elements in this direction.

The study is consistent with other work that has rather explored the causes of this trend. Thus, we suspect “causes such as obesity, lack of physical activity, pollution and exposure to chemicals in the environment,” recalled endocrinologist Channa Jayasena.

Other researchers, already skeptical of the 2017 study, clarified the findings of this new publication, believing that it did not eliminate all the shortcomings of the previous one. “I continue to question the quality of the studies, especially the older ones, (…) on which this new analysis is based,” said andrologist Allan Pacey, without questioning how the authors accomplished their compilation. The evolution of sperm count may actually reflect increasingly reliable methods of measurement rather than reality itself, he says.