Falling sperm counts and changes in sexual development threaten human survival and lead to a fertility crisis, a leading epidemiologist has warned.
In a new book, Shanna Swan, an environmental and reproductive epidemiologist at the Icahn School of Medicine on Mount Sinai in New York, warns that the looming fertility crisis poses a global threat comparable to the climate crisis.
“The current state of reproductive affairs cannot continue much longer without threatening human survival,” she writes in Count Down.
This comes after a study she compiled in 2017 found that sperm counts in the west dropped by 59% between 1973 and 2011 and made headlines worldwide.
Swan says, according to current projections, the median sperm in 2045 will be at zero. “It’s a little worrying, to say the least,” she told Axios.
In the book, Swan and co-author Stacey Colino examine how modern life threatens sperm counts, which alter the reproduction of men and women and endanger human life.
It indicates lifestyle and chemical exposures that alter and threaten human sexual development and fertility. This is the seriousness of the threats they pose, she argues, allowing humans to become an endangered species.
Of the five possible criteria for endangering a species, one only has to meet one; the current state of affairs for people meets at least three. ”
Swan offers advice on how to protect themselves from harmful chemicals and urges people to ‘do what we can to protect our fertility, the fate of humanity and the planet’.
Between 1964 and 2018, the global fertility rate dropped from 5.06 births per woman to 2.4. About half of the world’s countries have a fertility rate of less than 2.1, the population replacement level.
While contraception, cultural shifts and the cost of childbirth are likely contributing factors, Swan warns of indicators that there are biological reasons as well – including increasing miscarriage rates, more sex disorders among boys and earlier puberty for girls.
Swan blames ‘everywhere chemicals’, which are found in plastics, cosmetics and pesticides, which affect endocrine substances such as phthalates and bisphenol-A.
“Chemicals in our environment and unhealthy lifestyle practices in our modern world are disrupting our hormone balance, causing varying degrees of reproductive devastation,” she writes.
She also said factors such as tobacco smoke, marijuana and growing obesity play a role.