Common pesticides linked to male fertility risks

Common farm insecticides are not only killing pests but may also be chipping away at male fertility. A new review of 21 rodent experiments finds that a popular pesticide family consistently harms sperm in male rats and mice.

The work focuses on neonicotinoids, insect killing chemicals modeled on nicotine and used on farms.

Researchers at George Mason University (GMU) examined studies run between 2005 and 2025 to see how these compounds affected the reproductive systems of male animals.

How pesticides affect fertility

Many crops are treated with systemic pesticides, chemicals that move into every part of a plant. Once applied, residues can end up in leaves, fruit, nectar, and even the soil and water around fields.

Sumaiya S. Irfan, who led the research, studies how chemical exposures in everyday environments might influence reproductive health.

One national study tested urine samples from people in the United States and found that almost half had markers of at least one neonicotinoid. Scientists call this biomonitoring, testing blood or urine for traces of chemicals.

Another broad review of human exposure shows these insecticides in food, dust, water, and inside people far from farm work. That pattern matches their heavy use on large-scale crops and in pest control products for homes and pets.

Pesticide exposure and sperm quality

The new review included experiments on male rats and mice that tested different neonicotinoid pesticides, doses, and exposure lengths.

Each experiment tracked some part of the male reproductive system, such as sperm count, sperm movement, sperm shape, hormone levels, or testicular tissue.

“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,” said Veronica Sanchez, a researcher at GMU.

In many of the experiments, exposed rodents produced fewer sperm cells, had slower swimming sperm, or showed more oddly shaped sperm than unexposed animals.

Some studies also reported DNA damage and changes in the cells that produce testosterone, hinting at effects on hormone networks.

Similar pathways in humans

Mammals share the basic process of spermatogenesis, the way the body creates new sperm from stem cells in the testes. When that process goes wrong in rats and mice, it raises reasonable concern that similar pathways could be sensitive in humans.

Infertility is already widespread, with a global report estimating that roughly one in six adults of reproductive age are affected. In many couples, issues with sperm count, shape, or mobility are a major factor.

One human study looked at neonicotinoid markers in urine and found that levels lined up with lower testosterone in men, women, and children.

This pattern fits what scientists expect from endocrine disrupting chemicals, substances that interfere with normal hormone signals in the body.

A clinical study measured neonicotinoid metabolites in seminal plasma and saw that one imidacloprid breakdown product was linked to poorer sperm motility.

The findings do not prove cause and effect, but they echo the motion problems seen in the rodent experiments.

Everyday exposure in the real world

People encounter insecticides in many small ways, including residues on produce, drift from treated fields, house dust, and flea treatments for pets.

For most individuals, each exposure seems minor, yet the body may face a steady trickle over many years.

Animal studies point to oxidative stress as one way neonicotinoids can harm reproductive tissues. This term refers to chemical damage caused when reactive oxygen molecules overwhelm the cell’s protective systems.

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

Study co-author Melissa Perry emphasized the public health risks, noting that neonicotinoid use in United States agriculture has grown. She pointed out that exposures now occur routinely for many people who have no direct link to farming.

Reducing fertility risks of pesticides

People can lower their exposure a little by washing produce well and limiting pesticide use at home.

Even so, these chemicals often move through an entire plant, so rinsing only removes what sits on the surface. Being selective about what you buy helps reduce contact with them.

Practical steps include washing fruits and vegetables under running water, limiting use of sprays indoors, and checking labels to see which pesticides are applied. 

Some consumers choose to support farms that rely more on non chemical pest control, which can reduce direct contact with synthetic insecticides.

Future work will need to connect rodent data with stronger human studies that track long-term exposure and reproductive outcomes.

The study is published in the journal Environmental Research.

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