Candidate for Listing via the Authoritative Bodies Mechanism Found Not to Meet the Listing Criteria: Genistein
The California Environmental Protection Agency’s Office of Environmental Health Hazard Assessment (OEHHA) identified genistein as a potential candidate for listing as known to the state to cause reproductive toxicity under the Safe Drinking Water and Toxic Enforcement Act of 19862. This potential action was considered under the authoritative bodies listing mechanism3, based on the document, “NTP-CERHR Monograph on Soy Infant Formula” published by the National Toxicology Program – Center for the Evaluation of Risks to Human Reproduction (NTP-CERHR).
The NTP Monograph on Soy Infant Formula concludes that there is “clear evidence” that genistein, a constituent of soy infant formula, causes developmental toxicity in laboratory animals. However, OEHHA has determined that there is insufficient evidence that the criteria in Title 27, California Code of Regulations section 25306(g) for listing a chemical “as causing reproductive toxicity” have been met. For identification of reproductive toxicity (developmental toxicity endpoint) under Proposition 65, it is considered necessary that the evidence for developmental toxicity has resulted entirely or predominantly from prenatal exposure. That is not the case for genistein. The document concludes that there is “clear evidence of adverse effects of genistein in studies where treatment occurred during lactation”. The document further concludes that there is “clear evidence of adverse effects of genistein in studies with gestational, lactational, and post-weaning treatment”, but does not conclude that the effects could result entirely or predominantly from prenatal exposure.
For these reasons, OEHHA will not proceed at this time with the Proposition 65 listing process for genistein.