The widely held view that sperm counts in men are dropping around the world may be wrong, according to a new study by University of Manchester
The study which also included Queen’s University in Kingston, Canada and Cryos International, Denmark used data from 6,758 men from four cities in Denmark applying to be sperm donors at the world’s largest sperm bank, Cryos International, the study is published in the journal Human Reproduction today .
Declining sperm counts, identified by two recent and influential meta-analyses – combining and synthesizing the results of previous studies – have become widely publicized in the mainstream media.
In the new study, however, statistical analysis of sperm samples provided by the men applying to be sperm donors showed that while the average sperm concentration varied from year to year, it did not change significantly over a six-year period.
Although Cryos was established over 40 years ago, the researchers limited their analysis to data collected between 2017 and 2022 to ensure methodological consistency in the measurements of sperm concentration and motility – its ability to swim spontaneously.
Co-author Professor Allan Pacey from The University of Manchester said: “It is commonly believed by that sperm counts in men are falling.
“This is to some degree the result of meta-analysis published by Levine et al. (2023) which proposed that sperm concentrations worldwide had declined as much as 2.64% per year in unselected men since the year 2000.
“We did not see such a change and that suggests that in this population of sperm donor applicants, in these four Danish cities, sperm concentrations have not changed between 2017 and 2022”.
However, both the concentration and total numbers of motile (swimming) sperm provided for testing had declined by 16% and 22% respectively from 2019 to 2022.
