In the largest study of its kind, researchers find that sperm count in Western countries has more than halved in recent decades. Outside of these countries, however, the decline is not significant. Share on Pinterest Is sperm count really dropping in the Western world? The question of whether or not sperm count is declining has been hotly debated for many years within the scientific community. However, no firm conclusion has been reached. Of course, a reduced sperm count has important implications for reproduction, but this is not the only reason for alarm; low sperm count has been shown to increase the risk of all-cause mortality and morbidity. For instance, a study published in 2014 concluded that “those with abnormal semen parameters have a higher risk of death, suggesting a possible common etiology between infertility and mortality.” Also, reduced sperm count is associated with deformation of the penis (hypospadias), a testicle that has not moved into the scrotum (cryptorchidism), and testicular cancer. Another general concern is that sperm count and other measures of semen quality might be a sign that we are living in a toxic environment. The more we understand about this, the better we can approach making informed changes to the chemicals that we use every day.

Gathering data on sperm count With these factors in mind, a group of researchers recently set out to conduct a large-scale systematic review and meta-analysis of sperm count trends. For the study, a group from the Hebrew University-Hadassah Braun School of Public Health and Community Medicine in Israel joined forces with the Icahn School of Medicine at Mount Sinai in New York City, NY. Their results are published this week in the journal Human Reproduction Update. They screened 7,500 studies and completed a meta-regression analysis on 185 studies carried out from 1973 to 2011. The results were clear and surprising. Men from Europe, North America, Australia, and New Zealand had a 52.4 percent decline in sperm concentration and a 59.3 percent decline in total sperm count. In contrast, no significant decline was found in men from Asia, South America, and Africa – although there were fewer studies to analyze in these regions. Worryingly, the rate of decline in Western men did not appear to be slowing; “the slope was steep.” Even when the analysis was limited to studies from 1996 to 2011, the trend was still significant.