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3rd September 2025
Early onset puberty linked to chemical exposures from grandfathers
A grandfather’s exposure to endocrine disrupting chemicals (EDCs) may significantly influence the age at which his granddaughter begins puberty, potentially leading to earlier onset of menstruation.
This is the finding of new research which analysed data from the Child Health and Development Studies (CHDS). It measured chemical and metabolic profiles in blood samples from American couples in the 1960s. Decades later, this data was used to track the age of first menstruation in their daughters and granddaughters. They discovered that the median age of first period dropped by a full year from the daughters to the granddaughters generations.
But why?
Researchers identified that certain chemicals, including phenoxyethanol, a common ingredient found in toiletries, cosmetics, personal care products, and some foods were strongly linked to this earlier puberty, especially when both parents had high exposure. Phenoxyethanol is used as an antibacterial and antimicrobial preservative in 1000’s of everyday products, usually as an alternative to paraben ingredients. It a suspected EDC.
Parental exposures can result in changes in later generations
Earlier studies have identified that both maternal and paternal exposures can affect the timing of puberty, but in this research, paternal exposure showed a surprisingly strong influence, suggesting an important, previously unseen role of fathers and grandfathers in shaping endocrine health of later generations, in this instance, their granddaughters.
This is the first study to highlight that the father’s environmental exposures at conception and pregnancy can impact reproductive development in daughters and granddaughters. The findings underline the need to consider both parents’ environmental exposures to develop effective prevention strategies, as these effects can persist and influence health across multiple generations.
This population based data analysis suggests that paternal exposure to EDCs before or during pregnancy may be a critical factor in the rising incidence of early puberty among girls, emphasising the lasting impact of environmental chemicals on reproductive health across generations.
Early puberty in girls is more commonplace than it is in boys
Early onset of puberty in girls carries significant health risks, including greater chances of obesity, metabolic and cardiovascular disease, mental health issues, and social challenges. It also raises concerns about the emotional and readiness of girls which often do not match their physical development. The average age of puberty has lowered over time, with the average age for girls now between 11 and 12 years of age.
What can we do in everyday lives to reduce our exposure to chemicals?
This research highlights the need for better public information about the potential health effects of exposure to chemicals used in everyday products.
To help anyone who is concerned about the potential health effects of these exposures, we have developed a new test that will identify any recent exposures to 27 different types of chemicals, including parabens, phthalates, pesticides, VOCs, and bisphenols. It’s not quire ready yet, but you can register your interest using the form below, and we’ll let you know as soon as it is available.
The New Everyday Chemicals Test will help you understand which chemicals you have been exposed to by analysing metabolite markers in a urine sample. When you know your exposures, you can follow our simple steps guidance to start reducing your exposure, and avoid some of the chemicals altogether.
Read more about the research first presented at the Endocrine Society’s annual meeting
Learn more about endocrine disrupting chemicals