The sperm count in semen dropped 62% between 1973 and 2018, according to a global study by Israeli researchers. The declining sperm quality could cause serious fertility problems in the coming decades.
Although the decline in sperm quality has long been a concern of Western countries, a newly published meta-analysis of hundreds of scientific studies shows that the problem is global and the decline is accelerating, reported De Morgen.
Not only the total sperm count causes concern, but also sperm concentration. The average concentration in 1973 was at around 101 million sperm cells per millilitre. The number fell to 49 million per millilitre by 2018. The World Health Organisation is not yet sounding the alarm, however, should the number drop below the 40 million mark, fertility problems can arise.
That limit is in sight: between 1972 and 2000, there was an annual decline of 1.16 %, then the process accelerated to 2.64 % per year. "If this trend continues, by 2050 the average man will no longer be able to have children without help," urologist Piet Hoebeke (UGent) wrote on Twitter.
Israeli lead researcher Hagai Levine warned that declining sperm quality could threaten the survival of mankind if nothing is done about it. The only question is to what extent that is still possible.
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Hoebeke noted that the problem stems mainly from the many endocrine disruptors people come into contact with, which include substances like phthalates (used to soften plastic) as they can no longer simply be removed from nature or bodies. In the realm of fertility problems, they not only cause falling sperm quality but also increase the number of genital malformations.
"Women are born with a well-defined number of eggs, men are constantly producing new sperm. Because of this rapid cell division, they are much more sensitive to endocrine disruptors during reproduction," Hoebeke said.
The prospect of men being unable to have children on their own in 30 years' time is grim, but it may not come to that. For example, the study does not take into account the shape and quality of sperm, parameters that also have a significant impact on fertility. In addition, it is not obvious that the downward trend in sperm quality will simply continue.
"Endocrine disruptors can destroy a lot, but they cannot completely shut down hormonal functions. So there may be a levelling out. The only question is when," Hoebeke said.
In the meantime, he does think work needs to be done on a bold plan to prevent any more endocrine disruptors from invading our environment. "With the climate issue, there are clear goals to be pursued, there is also a need for that with seed quality."