The average size of the penis has grown by a quarter in the past 30 years, according to a Stanford University study. The cause? Probably our heavily polluted environment and chemical-laden food, experts suggest, which is also driving the sperm count crisis gripping our species.
The study, published in the World Journal of Men’s Health, analysed data from 75 studies involving 55,761 men from 1992 to 2021 and found the erect penis length had gone “from an average of 4.8 inches to 6 inches over the past 29 years”, study author Michael Eisenberg said.
The result took him by surprise considering the “trends we’d seen in other measures of men’s reproductive health”. Eisenberg added that the short time span during which the length grew meant “something powerful is happening to our bodies”. And not in a good way.
Fertility specialist at the University of Melbourne Alex Polyakov said the cause of this penis growth is likely to be twofold: young men entering into puberty earlier, and the number of chemicals they live with and ingest. But the two are also linked.
“The reasons for changes in pubertal timing remain unknown, but environmental factors have been suggested as possible culprits,” Polyakov told Crikey.
“For example, emerging data suggest that diverse prenatal or postnatal exposures may influence pubertal timing, such as exposure to endocrine-disrupting chemicals (EDCs) or obesogenic [obesity-prone] environments.”
Male fertility at risk
When it comes to the Stanford study, bigger is not better, said Mark Green, the deputy scientific director of Monash IVF Victoria, which runs a lab that looks at how EDCs — like BPA, parabens, and pesticides — affect fertility.
They’re found practically everywhere in the modern household, he said, and that should ring major alarm bells for men and women alike.
“Over the past two decades a large number of studies provide ample evidence that EDCs found in personal care products, food packaging and plastic containers, as well as many household products, can perturb our natural hormones to negatively affect our reproductive tracts and fertility in both men and women,” Green warned.
EDCs cause a cascade of issues in humans, like changes in hormone levels, damage to the DNA in sperm, longer menstrual cycles, pregnancy delays, increased risk of miscarriage, earlier menopause, and decreased sperm and egg quality.
Indeed human sperm counts appear to have fallen by more than 50% around the globe in the past half-century, and the decline in sperm appears to be accelerating from an average of 1.16% a year after 1973 to 2.64% after 2020.
Study author Hagai Levine called that finding “really remarkable”, adding it was clear “exposure to manmade chemicals that are in plastic, such as phthalates, disrupt the development of the male reproductive system”.
Easy ways to slash EDCs
The good news? The concentration of EDCs, like BPA, can be reduced via easy changes we can make to our lifestyle, as Green explained in a fact sheet he wrote for the Fertility Society of Australia.
For instance, choosing fruit and vegetables with a local origin where possible, and washing them well before eating, can reduce your exposure to pesticides, fungicides, herbicides and chemicals that may have been sprayed on the plants.
Green also recommended we try not to fill our trollies with too many pre-packaged or canned foods, which can have phthalates and plasticisers leached into them, and politely decline the receipt on the way out — the thermal coating contains BPA to give them their shiny plastic texture.
And ditch the potent detergents, hand sanitisers, cleaning agents and carpet cleaners that dominate shelves at the grocery store, instead going with the “green products” that use alternative non-toxic agents and smell a whole lot less intense.
Long shot about penis length?
There are a few reasons to be sceptical of the study’s, ahem, elongated finding, Polyakov qualified, namely that “penile measurements may be affected by temperature, arousal state, body size and investigator factors”.
He also pointed out there may be a hint of “volunteer bias” at play here — that is, proud, well-endowed men volunteering their bits for the studies over more modestly sized counterparts.
Green was equally a little sceptical about whether the average penis length had really grown in the past three decades, or whether it was a little bit of wishful thinking.
“Looking at the data, the authors report an increase in mean length of 1.4cm between 1990-2021, although the 1990 decade data only comprises of a very small number of studies,” Green pointed out.
“Therefore, this significant difference is unlikely to be biological, and is probably due to variation in the way measurements were taken in those two studies.”
