Recent research has highlighted a troubling trend: a significant decline in men’s sperm counts over recent decades. Since 1963, sperm counts have been decreasing at an annual rate of approximately 1.6%. By 2018, sperm counts were only half of what they were 50 years prior, with the decline accelerating to 2.6% per year since 2000.
Professor Hagai Levine from the Hebrew University of Jerusalem’s Hadassah Braun School of Public Health, who co-authored a study on this issue in 2018, has described these findings as a “canary in a coal mine.” He warns that if this trend continues, it could pose a serious threat to human survival.
Levine attributes the decline in sperm counts to potential epigenetic changes—alterations in gene expression influenced by environmental and lifestyle factors. Contributing factors include poor diet, sedentary lifestyles, stress, and substance abuse. However, environmental pollutants are increasingly being recognized as significant contributors.
A 2023 meta-analysis reviewing 25 studies found that exposure to certain pesticides was associated with significantly lower sperm concentrations. Additionally, research has linked fertility damage to chemicals in household products, air pollutants, and plastics.
A new dimension to this issue emerged from a study conducted by researchers at Qingdao University in China, who discovered microplastics in all semen samples from 40 healthy men. Previous studies in Italy and China also detected microplastics in 60% and 50% of sperm samples, respectively. Microplastics, tiny plastic particles less than five millimeters in size, are pervasive contaminants resulting from the breakdown of larger plastic waste. They have been found in various human tissues, including organs, feces, breast milk, placentas, and blood.
Although the impact of microplastics on human health remains unclear, laboratory studies suggest they can affect human cells. The presence of these particles in sperm samples raises new concerns about their potential effects on male fertility, adding another layer to the complex issue of declining sperm counts.
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