What is too small to see with the naked eye, manufactured by half the population in batches of millions and with an alarming supply? The answer, according to some scientists, is sperm. Specifically, researchers are concerned that men in the West have been producing less and less sperm since the 1970s, a decline they say shows no signs of stopping. At the current rate, they say, these men could be infertile by 2045. But these numbers should make us think. The idea that men's sperm in Western countries is about to collapse is, in a word, extraordinary. The data does not support it.
The fear of a decrease in sperm count is powerful and powerful. It has been voiced by everyone from environmentalists like Erin Brockovich to white supremacists and their mainstream media spokespersons like Tucker Carlson. The great appeal of this notion is possible because the supposed causes of a decline span the entire material and ideological gamut. They include chemicals found in common household products, as well as modern urban lifestyles in which white men are physically sedentary and forced to share power with people of constantly diverse genders and ethnicities. It's worth taking a closer look at the evidence before heading to the "save the sperm" rally. The most recent round of apocalyptic predictions was sparked by an influential 2017 article that compiled sperm count data from studies published between 1973 and 2011. Figures for the US, Canada, Western Europe, Australia, and New Zealand, is that is, rich countries, mostly white, were grouped in the "western" category and the remaining data were grouped in the "other" category. While there was insufficient data to draw conclusions about "other" men, the authors found that the sperm count of the average population among men in the "Western" category had decreased by more than 50% since 1973. We analyzed the data and found that the apocalyptic verdict of the disappearance of the sperm is far from the only plausible interpretation of what is happening here. The authors assume that the high sperm counts of men in "Western" nations in the 1970s represent the norm. This assumption makes the pernicious but all-too-common mistake of treating the men of prosperous, white-majority nations as the standard by which everyone else should be compared. It also takes for granted that when it comes to sperm, the more the merrier. The available evidence does not support this association: male fertility does not scale proportionally with sperm count. Some men with a low sperm count can be very fertile, while others who are overflowing with sperm can have a hard time conceiving. Add to this the well-known fact that sperm count is very context sensitive (to tight underwear, exercise, a hot bath, and even the season) and it's easy to see how a single sperm count measurement is an unreliable indicator of fertility. . There is also the question of what is causing the decrease in sperm count. If we take seriously the idea that environmental pollutants are hostile to sperm production, we would expect to see the most drastic declines among men living in the most polluted environments. It is well established that the world's poor, that is, those who live predominantly (but not exclusively) in the "other" countries, bear the greatest burden of environmental pollution. However, the authors and the media have launched into framing the crisis as one that confronts "Western" men; what is ignored is the fact that the study data were insufficient to draw conclusions for men in the "other" category. The very use of the categories "western" and "other" makes little scientific sense and matters dangerous racial nuances. Men frequently migrate between "western" and "other" nations, making countries a poor indicator of environments that could affect any man's sperm. And conditions vary widely within nations, especially large and heterogeneous ones like the United States or Brazil. Knowing which passport a man is carrying tells you little about contaminants or other possible sperm-reducing factors he may have encountered. Apart from all this, these seemingly alarming findings may simply reflect normal variation. This would be unprecedented - studies have documented natural ups and downs in the levels of reproductive hormones such as testosterone and progesterone, with no impact on fertility. Could sperm counts vary in the same way? The researchers don't even consider this possibility. The lesson from sperm depletion research is not that we are facing imminent human extinction (at least not for sperm-related reasons). Rather, it is the most banal but accurate fact that there is much we do not know about the relationship between men's reproductive health and environmental pollution. This blind spot is what we should pay attention to. A long and sexist history of scientists zealously focusing on female reproduction has led researchers to neglect male fertility. The legacy of chemical industry lobbying and industry-funded research distorts our understanding of the effects of plastics exposure on human health. And a racist history of treating rich white male bodies as the norm of the species sets us up to ignore the majority of the world's population. In the face of all this uncertainty and obfuscation, what we need is better science: scientific institutions free from corporate influence and diverse researchers trained to unearth hidden racist and sexist assumptions. Our failure to meet these standards is the real reason for the panic. Source:https://www.theguardian.com/commentisfree/2021/jun/07/scare-stories-falling-sperm-counts-male-infertility-science
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Octubre 2022
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