are men on their way to becoming 'subfertile'?
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a new book looked at a study of sperm and suggests the human population may drop soon.
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a new book by famed environmental and reproductive epidemiologist dr. shanna swan unleashed a bombshell claim that human penises and sperm count are shrinking at an alarming rate, to the detriment of global populations.
“what we found and published in 2017 was that sperm count had declined dramatically over the preceding 40 years and was at a point where nearly half of men would be…subfertile at least,” swan explained in an interview on lockdown tv. “if it were to continue on its present course, that’s a difficult thing to project, but just mathematically if you’ve extended the line it does hit zero in 2045.”
the book is based on an article from the hebrew university of jerusalem (swan is listed as an author). researchers conducted a meta-analysis of english-language studies that dealt with human sperm count from 1981 to 2013. they ended up analysing data from what can only be described as a boat-load of semen: 244 estimates from 42,935 men.
the results indicated a significant decline in sperm count in samples from western populations (north america, europe, australia and new zealand) at 1.6 per cent per year, and an overall decline of almost 60 per cent from 1973 to 2011. similar studies conducted in africa, asia, and south africa, have not shown a similar decline, however, vice notes that this may also be due to fewer long-term studies being conducted in these regions.
although the study did not target a cause of decreasing sperm counts, sawn believes that increasing presence of chemicals in our daily life, like phthalates, bpa, parabens and atrazine, are a major factor in this development.
“phthalates…have the ability to lower testosterone,” swan explained. “if the pregnant woman is exposed to phthalates in early pregnancy, these phthalates can reduce foetal testosterone at a critical time for male genital sexual development. this was first shown in rodents, and it was so striking that it was named the phthalate syndrome.”
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phthalates are a common component in many items made from plastic, like packaging and vinyl flooring.
not everyone is convinced
swan’s concern over decreasing sperm counts is made very apparent in this book, with swan going so far as to suggest that the human species may go extinct from these infertility issues.
not everyone is convinced, however.
“the book does not seem sensible,” tom chivers, science editor for unherd wrote in a recent review. “because for swan, everything causes fertility problems, not just phthalates. sugar, beef, cycling, stress, watching tv, doing too much exercise, doing too little, eating the wrong diet; you can barely get out of bed in the morning without sabotaging your chance of having a baby.”
“it seems bizarre to suggest that this is going to lead to human extinction”
chivers also points to recent improvement in health that should improve fertility rates – like a decrease in the number of people who smoke. other improvements in fertility treatments and surrogacy may also push back on the alarm.
regardless of fertility treatments, however, there is no denying that the global population is headed for a steep decline in the next century. what’s more, the west and southeast asia are already there.
global population already on the decline
the finding that male fertility is falling comes on the heels of another major study released in 2020 that says the global population will sharply decline by the end of the century.
published in the lancet, models suggest the world’s population will peak at 9.73 billion people by 2064, and then sharply decline to 8.79 billion by 2100. (the current global population is estimated to be 7.75 billion according to the u.s. census bureau.)
“that’s a pretty big thing; most of the world is transitioning into natural population decline,” researcher prof christopher murray told the bbc.
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“i think it’s incredibly hard to think this through and recognise how big a thing this is; it’s extraordinary, we’ll have to reorganise societies.”
as the birth rate around the world decreases, there will also come a major shift in age demographics, with more people over the age of 80 alive than ever before. in an aging population, the burden is disproportionately placed on the young for work, elder care, and taxes.
the research suggests a major cause of the decline is due to an increase in access to contraception as well as more women obtaining higher levels of education. researchers also projected that if the sustainable development goals for education and contraceptives are met, global population would be 6.29 billion by 2100.
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