Sperm counts and concentrations declining globally since 1970s but fertility implications unknown: study

A controversial paper published in the journal Human Reproduction Update notes that sperm counts have declined globally by about half since the 1970s — but experts are cautious about the results.

"It is the first study to examine global trends in semen quality in recent years and the first to demonstrate declining sperm counts among men from South and Central America, Asia and Africa," said lead author Hagai Levine, professor at Hebrew University of Jerusalem’s Hadassah Braun School of Public Health. The study concluded there is a global decline in sperm concentration not only in North America, Europe and Australia, but also in South and Central America, Africa and Asia.  "Luckily for us, the methods for counting sperm are rather simple and haven't really changed in the last 50 years." "We can summarize that there is strong evidence for global decline, including in Latin America, Asia and Africa, but we can't be certain for a specific population or country." "In 2020, the global population growth rate fell under 1 percent per year for the first time since 1950." 

But many experts in the scientific community remain skeptical of the findings.