Repost NU.nl
Written by Lennart 't Hart
The sperm production of men worldwide is declining faster than we already thought. Researchers fear that we are approaching a tipping point. Then the fertility of the majority of men will be at risk.
Research from 2017 found that sperm count in Western men in a single ejaculation dropped by more than 50 percent between 1973 and 2011.
The same researchers looked at what has happened in the last decade. To do so, they looked at multiple studies between 2014 and 2019 on sperm. Then they added that data to their old data.
They concluded that between 1973 and 2018, the average sperm concentration dropped from 101 million sperm to 49 million sperm per milliliter. That's a 51.6 percent drop. And since 2000, that annual decline has been accelerating.
The new data includes sperm samples from men from South and Central America, Africa and Asia. The new study would therefore provide a better picture worldwide than the 2017 analysis.
'Global seed crisis we must address now'
According to lead researcher Hagai Levine at the Hebrew University of Jerusalem, there is a global seed crisis. "We need to address that now, before we reach a tipping point that may not be reversible," he says.
Previous studies have shown that fertility is compromised when the sperm concentration falls below 40 million sperm per milliliter. Although the average is still above that amount according to the latest estimates, eventually there will be more and more men who do not exceed the 40 million threshold, Levine believes.
On average, the number of sperm cells per ejaculation is usually between 40 and 300 million per milliliter.
Fertility decreases due to chemicals and smoking
The study also has limitations. For example, it did not look at sperm quality. Nor did it look at what causes the decline, although there are several theories about this. One is the increase in chemicals that pregnant women pass on to the baby in the womb.
Many experts also agree that factors such as smoking, drinking, obesity and poor nutrition have a negative impact on sperm production.
The study was published in the scientific journal Human Reproduction Update.