Organophosphate pesticide exposure linked to reduced sperm quality in healthy men

By Hugo Francisco de SouzaReviewed by Susha Cheriyedath, M.Sc.Sep 25 2025

Researchers have found that everyday pesticide exposure can impair sperm motility, providing early evidence that male reproductive health may be at risk through mechanisms beyond oxidative stress.

Study: Organophosphate Pesticide Exposure and Semen Quality in Healthy Young Men: A Pilot Study. Image Credit: AstroStar / Shutterstock

In a recent study published in the journal Antioxidants, researchers at NYU Grossman School of Medicine and the University at Albany in the United States conducted a cross-sectional pilot study to explore the link between chemical exposures (specifically, organophosphate (OP) pesticide exposure) and semen quality in a cohort of 42 healthy young adult men.

The study leverages multiple data sources (e.g., urinary metabolites, semen oxidative stress) and found that higher levels of pesticide metabolites were associated with lower sperm motility, a key predictor of male fertility. Surprisingly, oxidative stress was not found to be a mediator of these observations, suggesting that other biological pathways may be at play.

Background

Male-factor infertility, the inability of a man to initiate pregnancy despite repeated sexual intercourse, contributes to approximately half of all infertility cases in the United States. Caused primarily by semen or sperm deficiencies (e.g., low sperm count [oligospermia]), evidence attributes the growing surge in male-factor infertility to a century-long decline in semen quality, especially in industrialized nations.

Studies suggest that the increased production and use of endocrine-disrupting chemicals (EDCs), including organophosphate (OP) pesticides, have substantially increased male-factor infertility. Previous research consistently links high-dose occupational exposure to OP pesticides with poor semen quality.

Unfortunately, very few of these studies have explicitly used biological markers to examine the effects of low-level, everyday exposures that most men experience, and more importantly, unravel their mechanistic underpinnings. However, given previous research, the oxidative stress caused by OP pesticides is hypothesized to primarily drive these EDCs' contributions to male infertility.

About the study

The present study aims to address this knowledge gap by providing the outcomes of a pilot study investigating the relationship between OP pesticide exposure and male infertility, and further testing whether oxidative stress is the mediating factor in observed outcomes.

The study recruited a cohort of healthy male participants (n = 42) between the ages of 18 and 45, excluding men with relevant urological conditions or those using fertility-affecting medications from the sample. For analysis, one underweight and two class 3 obese participants were also excluded. Data collection was carried out through detailed questionnaires (health and lifestyle), morphometric evaluations (height and weight), and the collection of biological samples (urine and semen).

High-performance liquid chromatography–electrospray ionization–tandem mass spectrometry (HPLC-ESI-MS/MS) was employed to determine the urinary concentrations of dialkylphosphate (DAP) metabolites, which are well-established biomarkers of OP pesticide exposure.

World Health Organization (WHO) standards were maintained in assessing semen quality. These assessments focused on three key parameters: sperm concentration, motility (the percentage of sperm that are moving), and morphology (the percentage of sperm with a regular shape).

Notably, a novel galvanic cell-based technology called MiOXSYS was used to measure participants' seminal oxidation-reduction potential (ORP). This metric serves as an integrated marker of oxidative stress in the semen, elucidating the contribution of oxidative stress to observed semen quality.

Statistical models (bivariate analyses, linear and logistic regression models) were finally used to analyze the associations between the pesticide metabolite levels and the semen quality parameters. Analyses were unadjusted, as potential covariates did not differ meaningfully between groups.

Study findings

Statistical models suggested an association, though the confidence interval crossed 1.0, indicating borderline statistical significance, between pesticide exposure and reduced sperm motility. A 1-log unit increase in the total concentration of urinary DAP metabolites was associated with a 163% increase in the odds of having low sperm motility (Odds Ratio [OR]: 2.63, 95% Confidence Interval [CI]: 0.98, 9.03). High-throughput HPLC-ESI-MS/MS analyses found that this association was primarily driven by the diethyl (DE) class of OP metabolites.

Unexpectedly, while higher levels of seminal ORP (indicating greater oxidative stress) were strongly associated with lower sperm concentration (OR for low concentration: 3.95, 95% CI: 1.41, 18.93), there was no association between pesticide exposure and seminal ORP. Furthermore, seminal ORP was not observed to be statistically associated with sperm motility.

These results suggest that while OP pesticides impair sperm motility, they do so through a mechanism other than the one measured by seminal ORP. Potential mechanisms may include alternative biological pathways, such as the disruption of acetylcholine signaling, which is crucial for sperm movement, or direct damage to the mitochondria that power the sperm's tail.

Conclusions

The present pilot study represents the first systematic attempt to establish associations between routine, non-occupational exposure to OP pesticides and a decline in semen quality among healthy young men.

While the small sample size means the findings should be interpreted with caution and their generalizability is limited, the study's findings provide preliminary evidence that OP pesticide exposure may be linked to reduced sperm motility. Fertility outcomes were not directly assessed.

These findings underscore the need for larger studies to confirm this association and unravel its mechanistic underpinnings. The study also suggests the need for a potential re-evaluation of the regulations governing OP pesticide use in the food supply. Such findings are hypothesis-generating and may contribute to the evidence base informing future risk assessments and regulatory decisions.