Common pesticides may cause testicular damage and lower sperm counts

Researchers from George Mason University's College of Public Health and College of Science, led by alumna Sumaiya Safia Irfan and student Veronica Sanchez, examined 21 experimental studies conducted between 2005 and 2025. Their comprehensive review found consistent evidence that exposure to insecticides can negatively affect human health, particularly male reproductive health.

"We concluded it is possible that exposure to these chemicals can lower sperm quality, disrupt hormones, and damage testicular tissue," said Irfan, the study's first author and a master of public health in epidemiology graduate from George Mason.

Widespread Use of Neonicotinoids Raises Concerns

The research focused on neonicotinoid pesticides (neonics), the most extensively used class of insecticides worldwide. These chemicals are commonly applied to crops, where they are absorbed into the soil, water, and plant tissues. Because of this, residues may remain in foods consumed by humans.

To understand potential health effects, Irfan and Sanchez reviewed data from animal studies examining how neonics impact male reproductive health in rodents.

"Many individuals may not realize that insecticide residue found on food could be a contributing factor to infertility. All studies included in this review reported that neonicotinoid exposure was harmful to sperm quality in the male rats and mice," said Sanchez, a master of science in chemistry student and research assistant at the George Mason Center for Applied Proteomics and Molecular Medicine.

Possible Links to Infertility Require Further Study

Although animal research offers critical insights, the full effects of neonic exposure on human reproduction remain uncertain. The authors agree that the findings warrant more investigation before conclusions can be drawn about human health risks.

"These findings warrant pause for reflection, as the extent of the effect of neonics on human health is not yet fully understood," said Sanchez, who will graduate in fall 2025. "There needs to be further research into the effects of neonics on humans so we can begin to discuss mitigation strategies."

Melissa Perry, Dean of the College of Public Health and a contributing author, emphasized the importance of continued research.

"Neonicotinoid insecticide use in U.S. agriculture has grown significantly over the last decade, so we know that exposures happen routinely for a large number of people. We need to conclusively determine how this affects members of the American public," said Perry.

Reducing Exposure to Pesticides at Home

The U.S. Food & Drug Administration (FDA) recommends seven key steps for cleaning fruits and vegetables to remove dirt, surface preservatives, and other residues from farming processes. However, Irfan noted that while washing produce can help reduce some contaminants, it cannot eliminate pesticides that are absorbed throughout the plant.

"In general, you can reduce pesticide exposure by thoroughly washing produce before eating and by minimizing conditions that attract pests into your home that would require you to use some form of pest control. However, because neonicotinoids are often applied systemically, meaning they are absorbed by the plant and present throughout its tissues, they are very difficult if not impossible to remove completely. The best way is to be aware of what you are buying and shop responsibly," Irfan said.

Ongoing Research into Chemical Impacts

The study, "Reproductive Risk of Neonicotinoids: A Review of Male Rodent Studies," was published in the December 2025 issue of the Journal of Environmental Research.

Contributing authors from George Mason University include faculty members Michael Bloom, Helen Chin, Jenna Krall, and Anna Pollack from the College of Public Health, and Virginia Espina and Lance Liotta from the College of Science.

Their collective findings add to growing evidence that modern agricultural chemicals, while vital to crop protection, may carry unseen risks that deserve closer scientific scrutiny.