PFAS, often called “forever chemicals”, are now found almost everywhere — in consumer products, the environment and inside our bodies. As evidence grows about their effects on human health, researchers have begun examining whether these long-lasting chemicals can also influence fertility, including sperm health and reproductive outcomes.
Firstly, what are PFAS?
PFAS (per- or poly-fluoroalkyl substances) are a group of thousands of different human-made chemicals. There are no naturally occurring PFAS.
PFAS are used in almost all industries and many consumer products, including plastics, clothing and personal care products, because of their useful chemical properties. These same properties also result in widespread pollution because PFAS breakdown is extremely slow (that’s why they’re called forever chemicals), causing accumulation in the environment and in our bodies.
Fewer than 20 of the thousands of PFAS used around the world have been thoroughly investigated for their toxicity, and all of those tested are capable of causing harm to animals (including humans). There is also lots of evidence showing harmful effects of PFAS on humans and other animals.
How do PFAS affect fertility?
PFAS accumulate in the body and have widespread effects, including in the male and female reproductive systems, and on the health of offspring. There is convincing evidence from studies using experimental animals, showing multiple effects of PFAS on reproduction and demonstrating the cellular and biochemical effects (including oxidative stress and endocrine disruption). Evidence from human studies confirms some of the effects seen in experimental animals, including increased risk of preterm birth and miscarriage, decreased sperm motility (movement) and damage to the DNA in sperm, but inconsistent effects on growth of unborn babies and no overall effect on fertility (although infertility due to polycystic ovary syndrome and endometriosis in females might be increased).
As is often the case in biomedical research, effects in humans are more difficult to demonstrate than in laboratory experiments. There are lots of variables in humans that cannot be controlled for, and outcomes in human studies are often less precise than the measurements obtained from experimental animals. In the case of PFAS effects on male infertility, the more limited effects seen in humans (compared to experimental animals) are likely due to limitations of the available data. It’s more a case of there being a lack of sufficient data to show an effect that is real, rather than there being sufficient data showing a real lack of effect.
So do PFAS cause male infertility?
PFAS are unnatural chemicals that have become distributed to all corners of the globe. We can find them everywhere we look, including inside our bodies, and there is strong evidence to show that they disturb normal biological functions. PFAS probably do influence male fertility, but the effect may be small.
If there is even a small effect of PFAS on male fertility, we should do what we can to minimise it because these chemicals will be in our environment and in our bodies, and their effects will continue, for years to come. For optimal fertility, it’s sensible to add ‘avoid PFAS’ to the list of preconception health habits that include maintain a healthy weight, eat a healthy diet, do sufficient physical activity, avoid alcohol and don’t smoke or vape.
How can you avoid PFAS?
The PFAS horse has already bolted. Anything we do to avoid PFAS now will minimise future accumulation in our bodies but elimination of PFAS already in our bodies will take many years. PFAS are inescapable, which is why better regulation of these chemicals (and their replacements) is critical for minimising future exposure.
Any personal actions we take to minimise our exposure to PFAS are likely to have only small effects, so it makes sense to prioritise other healthy behaviours that will have greater and faster benefits.
Tim Moss
Healthy Male Health Content Manager
Dr Tim Moss has PhD in physiology and more than 20 years’ experience as a biomedical research scientist. Tim stepped away from his successful academic career at the end of 2019, to apply his skills in turning complicated scientific and medical knowledge into information that all people can use to improve their health and wellbeing. Tim has written for crikey.com and Scientific American’s Observations blog, which is far more interesting than his authorship of over 150 academic publications. He has studied science communication at the Alan Alda Centre for Communicating Science in New York, and at the Department of Biological Engineering Communication Lab at MIT in Boston.
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