Birth defect - A physical or biochemical defect (as cleft palate, phenylketonuria, or Down syndrome) that is present at birth and may be inherited or environmentally induced.

Reproductive toxicant - Substance or preparation that produces non-heritable adverse effects on male and female reproductive function or capacity and on resultant progeny.


No regulatory authority in the world considers chlorpyrifos a cause of birth defects or a selective reproductive toxicant. Despite extensive use of the product for more than 45 years, there is no credible scientific information that would substantiate such a claim. The U.S. Environmental Protection Agency, the U.S. Centers for Disease Control, the California Department of Pesticide Regulation, the World Health Organization, and many other regulatory authorities worldwide have evaluated decades of research on chlorpyrifos and have not found birth defects or reproductive toxicity to be plausible outcomes of exposures from authorized use. Most recently, during 2008 the California Office of Environmental Health Hazard Assessment’s DARTIC (Developmental and Reproductive Toxicant Identification Committee) evaluated available data on chlorpyrifos and concluded that it should not be added to California’s Proposition 65 list based on lack of evidence of developmental or reproductive toxicity.

Further Resources

Breslin, W.J. et al. “Evaluation of the developmental and reproductive toxicity of chlorpyrifos in the rat.” Fundamental and Applied Toxicology, 1996, Volume 29(1):119-30.

Maurissen, J.P. et al. “Lack of selective developmental neurotoxicity in rat pups from dams treated by gavage with chlorpyrifos. “ Toxicological Science, 2000, Volume 57(2):250-63.

U.S. Department of Health & Human Services. Environmental Health & Toxicology site. IUPAC glossary:

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