Recent studies show that over the past 50 years, the number of sperm in men has decreased by half. The researchers’ findings sparked a debate among experts about male fertility.
How writes CNN, if these alarming data are confirmed and the decline continues, this will have negative consequences not only for the reproductive system, but also for the health of men in general. The researchers argue that sperm quality may be an important marker of the process.
The review and conclusions caused much controversy among experts. Some say that the results are real, but others are not sure because the methods of counting have changed over time so much that it is impossible to compare historical and modern figures. Stanford Medicine urologist Dr. Michael Eisenberg says:
“There is a strong link between a man’s reproductive health and his overall health. So it could also mean that maybe we’re not as healthy as we used to be.”
Dr. Alexander Pastuchak, surgeon and assistant professor at the University of Utah School of Medicine in Salt Lake City, argues:
“The way semen is analyzed has changed over the past decades. He has improved. It has become more standardized, but not ideal. Even if you take the same sample and analyze semen in the 1960s and 70s, compared to today, you will get two different answers.”
The latest study updates a review published in 2017 and includes data from Central and South America, Asia and Africa for the first time. The analysis was published in the journal Human Reproduction Update.
An international team of researchers studied almost 3,000 samples that recorded male sperm counts and were published between 2014 and 2020, years that were not included in the previous analysis.
The researchers determined that sperm counts were declining by just over 1% per year between 1973 and 2018 and concluded that by 2018, global average sperm counts had fallen by 52%. When the scientists limited their analysis to specific years, they found that the decline in sperm count seemed to be accelerating, from an average of 1.16% per year after 1973 to 2.64% per year after 2020. Study author Dr. Hagay Levin, an epidemiologist and public health researcher at the Brown School of Public Health and Community Medicine, said:
“It’s really remarkable that the decline is actually increasing. This should be studied. We know that maternal stress, maternal smoking, and especially exposure to artificial chemicals found in plastics such as phthalates disrupt the development of the male reproductive system. The same factors that are detrimental to overall health are usually detrimental to sperm quality as well.”
Dr. Scott Lundy, urologist at the Cleveland Clinic, says:
“While this is not a cause for panic, since the indicators are still generally normal, on average there is a risk that they may become abnormal in the future, we must acknowledge this and conduct further research.”