Study link early puberty in girls to their grandparents

A new American study has discovered an unexpected connection between the environment in which our grandparents and the reproductive health of their granddaughters lived. According to researchers, the exhibition of grandparents to chemicals called endocrine disruptors It may have advanced the age at which many girls begin menstruation.

These products – present in cosmetics, containers, cleaning products, food or water – alter the hormonal system and Its effects can be transmitted from generation to generation.

The study has been led by Xin HuResearcher at the Rollins Public Health School of the University of Emory in Atlanta (United States), together with Barbara Cohndirector of the Child Health and Development Studies (CHDS) at the Berkeley Public Health Institute (California). The results were presented at the Annual Congress of the Endocrine Society (Endo 2025)held in San Francisco.

Researchers have worked with CHDS data, a study that began in the 1960s. From blood samples taken to 249 couples at that time, the team has analyzed how its exposure to certain chemicals affected, decades later, its daughters and granddaughters.

While the average age of the first menstruation remained stable between grandmothers and their daughters, in The granddaughter’s case was observed a full year advance. The granddaughters born around 1990 began puberty before.

The team found links between the moment when girls began puberty and certain chemical substances detected in the blood of their grandparents, such as the Phenoxietanola common preservative in cosmetics and food. The effect was even greater When both parents – grandfather and grandmother – had been exposed to the same substances.

Until now, most studies have focused on how the mother’s environment affects pregnancy. But this work shows that Father’s exposure also significantly influences.

“Paternal exposure to environmental chemicals can play an unrecognized, but crucial role in the formation of endocrine health of descendants,” he explains Xin Hu.

“Our results highlight the role of endocrine disruptors during pregnancy and conception,” he says Barbara CohnCo -author of the study.

The team insists that Identify and reduce exposure to these substances can be key to protecting future generations. The study underlines the importance of applying a broader vision of family health, which also includes the environmental history of parents and grandparents.