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Sperm counts in men all around the globe seem to be plummeting, and scientists aren’t sure why. A 2022 study published in the journal Human Reproduction Update – a meta-analysis of 223 previous studies – looked at 57,000 men in 53 countries across six continents. The study found that from 1973 to 2018, the average sperm concentration fell by 51.6 percent – from 104 million to 49 million per milliliter of semen. Total sperm counts fell by 62.3 percent during the same period. Looked at another way, sperm counts dropped by 1.2 percent a year from 1973 to 2000, "which is a lot," said epidemiologist Hagai Levine of the Hebrew University of Jerusalem, who helped lead the research. From 2000 to 2018, the decline was 2.6 percent per year, "which is an amazing pace," he said.
But should people be concerned? In the near future, this is unlikely to cause major reproductive issues for humanity as a whole because the average sperm concentration of 49 million per milliliter is still above the 40 million threshold below which fertility may be affected. Sperm count is not an entirely reliable way to measure fertility, and some scientists have suggested that the data may partly reflect improved accuracy in counting sperm levels with modern techniques. However, Levine notes that this lower average sperm concentration means that many men are below the 40 million threshold, so it may take longer to have children, and very large families may become less likely.
An alarming decline?
- “I think this is another signal that something is wrong with the globe and that we need to do something about it. So yes, I think it’s a crisis, that we [had] better tackle now, before it may reach a tipping point which may not be reversible,” Levine said, with many other scientists echoing his concerns.
- There are many factors that can reduce a man’s sperm count, such as environmental toxins, a sedentary lifestyle, smoking, poor diet, and obesity. On the other hand, an active lifestyle and a healthy diet may help boost sperm levels.
- Obesity appears to be quite a significant factor. When a man carries excess weight, his hormone levels change, with an increase in estrogen. The male reproductive organs can also be affected by increased temperature linked to an unhealthy weight.