Marcia Herman-Giddens at the University of North Carolina at Chapel Hill, US, who first noted the declining age of puberty in US girls in a landmark 1997 study, says the findings are further cause for alarm.
There are huge health and social complications,” Herman-Giddens warns. “Imagine being eight or nine years old and having men hit on you because you have breasts. Grown women have enough trouble dealing with unwanted sexual advances – imagine being in the fourth grade.”

She adds that girls who start puberty early do not do as well in school, are more likely to be depressed, and engage in early sexual activity an alcohol use. She notes that other factors, including girls growing up without their father in the home, lack of exercise, and endocrine disruptors - chemicals common in pesticides - could also be playing a role in the early onset of female puberty.

Previous studies have also shown that early puberty leads to increased rates of reproductive cancer later in life.