The biggest risk factors associated with early puberty are obesity, toxic stress (things like food insecurity and witnessing violence), and environmental triggers such as chemicals, though Greenspan says we really need more research to nail that last one down.

“The questions I get are, ‘is it the hormones in the milk?’, ‘is it the chemicals in the sunscreen?’, and the biggest cause is obesity,” she said.

Apart from just cutting a girl’s physical childhood short, early puberty is linked to consequences that can reverberate throughout her life. It’s linked to greater risk for breast cancer, teen pregnancy, HPV, heart disease, diabetes, and all-cause mortality, which is the risk of dying from any cause.

There are psychological risks as well. Girls who develop early are at greater risk for depression, are more likely to drink, smoke tobacco and marijuana, and tend to have sex earlier.

It’s not clear exactly why this is, though “we do know that being a late bloomer or early bloomer and standing out from your peers can be a stress for some kids,” Greenspan said.

Another negative contributing factor could be the way young girls’ bodies are sometimes sexualized by companies and the media, which could affect their body image or push them toward behaviors they’re not ready for. Greenspan gave an example.

“I went into a popular, well-known store, trying to buy my 7-year-old daughter a cute sundress. There was this tiny little off-the-shoulder giraffe print thing in the window and of course, it’s giraffe print, so my daughter goes, ‘Mommy, I want that, it’s cute!’ And I said ‘Nope, the store got confused and they made a teenager outfit in little-kid sizes.’ And I left the store.”