I figure this story is either an academic boondoggle or the advance warning of a crisis as important as climate change. Either way, I leave it to you to decide:
It has been reported in the Guardian no less, that some scientists believe we are seeing a catastrophic collapse in reproduction rates due to falling sperm counts. This collapse will lead “most couples … to use assisted reproduction by 2045.”
This news comes from an interview with
“Shanna Swan, professor professor of environmental medicine and public health at Mount Sinai school of medicine in New York City, studying fertility trends. In 2017 she documented how average sperm counts among western men have more than halved in the past 40 years. Count Down is her new book.
Which chemicals are the most worrying for reproductive health and how do they work?
Those that can interfere with or mimic the body’s sex hormones – such as testosterone and oestrogen – because these make reproduction possible. They can make the body think it has enough of a particular hormone and it doesn’t need to make any more, so production goes down.
Phthalates, used to make plastic soft and flexible, are of paramount concern. They are in everybody and we are probably primarily exposed through food as we use soft plastic in food manufacture, processing and packaging. They lower testosteroneand sohave the strongest influences on the male side, for example diminishing sperm count, though they are bad for women, too, shown to decrease libido and increase risk of early puberty, premature ovarian failure, miscarriage and premature birth.
Bisphenol A (BPA), used to harden plastic and found in cash-register receipts and the lining of some canned-food containers, is another. It is oestrogen mimicking and so is a particularly bad actor on the female side, increasing risks of fertility challenges, but likewise it can affect men. Men occupationally exposed to BPA have shown decreased sperm quality, reduced libido and higher rates of erectile dysfunction. Other chemicals of concern include flame retardants and certain pesticides such as atrazine.
How dire is the reproductive crisis? You’ve said we are on course for an infertile world by 2045…
It is serious. If you follow the curve from the 2017 sperm-decline meta-analysis, it predicts that by 2045 we will have a median sperm count of zero. It is speculative to extrapolate, but there is also no evidence that it is tapering off. This means that most couples may have to use assisted reproduction.
Remember, of course, she has a book to sell.