Male reproductive health has declined in many developed countries over recent decades, with falling sperm counts and testosterone levels raising widespread concern. PFAS exposure is increasingly recognized as a contributing factor to male reproductive dysfunction, operating through hormonal disruption and direct testicular toxicity.
PFAS and Sperm Parameters
Semen analysis typically evaluates sperm concentration, motility, morphology, and total count — all parameters that influence fertility. Studies from Europe and the United States have found that men with higher PFAS blood levels tend to have lower sperm concentration, reduced motility, and greater proportions of morphologically abnormal sperm.
A particularly notable study of young Danish men found that those with the highest PFAS exposures had approximately 6% lower sperm concentration and 10% lower total sperm count compared to those with the lowest exposures. These reductions, while seemingly modest, could meaningfully affect fertility in men who are already near the threshold for subfertility.
Testosterone and Hormonal Effects
PFAS appear to disrupt androgen — particularly testosterone — production and signaling. Several mechanisms have been proposed, including inhibition of steroidogenic enzymes in the testes (particularly 3β-HSD and StAR), disruption of luteinizing hormone (LH) signaling, and altered expression of androgen receptors.
Epidemiological data show inverse associations between serum PFAS levels and testosterone in men across age groups. Studies of occupationally exposed workers have found significantly lower testosterone levels compared to unexposed controls. General population studies using NHANES data have confirmed these associations at lower exposure levels typical of the general population.
Testicular Cancer Risk
Testicular cancer is one of the cancers with the strongest and most consistent associations with PFAS exposure. It primarily affects young men aged 15–35, and its incidence has increased in many countries over recent decades. Studies of communities near PFAS manufacturing facilities and military bases using AFFF (aqueous film-forming foam) have found elevated rates of testicular cancer.
The testis is particularly vulnerable to PFAS because its blood-testis barrier does not exclude PFAS effectively, and Sertoli cells and Leydig cells — which produce sperm and testosterone respectively — are directly exposed to circulating PFAS.
Protecting Male Reproductive Health
For couples experiencing fertility challenges, assessing and reducing PFAS exposure is a reasonable component of a comprehensive evaluation. While PFAS-related reproductive effects may take years to manifest, reducing ongoing exposure through water filtration can limit cumulative testicular burden.
Young men living in areas with PFAS-contaminated water supplies may particularly benefit from filtration systems that remove PFAS from drinking and cooking water. The critical period for testicular development during puberty may make adolescent males especially vulnerable to PFAS reproductive toxicity.