It might seem like teenage girls are looking younger and younger each year, but there’s some truth to that. Researchers are finding that the age of onset puberty has been declining over the years, and girls are beginning to physically resemble grown women at younger ages.

A 2010 study put out by “Pediatrics,” the American Academy of Pediatrics’ (AAP) journal, followed a cohort of 1.2K+ girls between the ages of six and eight years of age from New York, Cincinnati and San Francisco. The study measured breast “budding,” normally the first physical step in female puberty. The results found that girls were beginning this stage around ages seven or eight, which is earlier than girls who were born only 10 years ago. (Incidentally, there was no change in age of first menstruation.)

This is even earlier than what was found in a previous AAP study completed in 1997. That year, results showed that girls began puberty between eight and nine years of age.

So what’s been causing the change? There appears to be a link between sugary drinks and early onset puberty for girls. The study defined early puberty as age of first menstruation, but not by breast budding.

It appears more research is needed, but this is an issue that needs to be addressed sooner rather than later.