It seems girls go through puberty much earlier these days. Why?


It’s true many girls reach puberty earlier today. Although the exact cause is not known, researchers suspect estrogen-promoting chemicals in the environment, obesity, and dietary factors to be the culprits.

Earlier than ever

Today it’s common for girls to begin developing breasts at age eight—once considered abnormally young—and to begin menstruation at age 12. Earlier puberty not only may cause emotional pressures, but also may raise the risk of breast and ovarian cancer due to longer exposure to estrogen.

Estrogen-promoting chemicals

Common chemicals in our environment today boost estrogen activity, which can trigger puberty early. These include pesticides, flame retardants, BPA (in tin cans, baby bottles, toys, and other food packaging), phthalates (in cosmetic products, PVC, plastics, food packaging, and numerous products), and parabens (in shampoos and cosmetic products). Phthalates have also been linked with abnormal hormone development in boys, and prenatal exposure to these chemicals has also been identified as a risk factor.


Studies also link obesity with early puberty. An ample diet signals to the brain that conditions are safe for reproduction, and body fat produces estrogen. Overweight and obese children often have higher insulin levels—insulin stimulates the production of sex hormones. For this reason, a diet high in starchy carbohydrates (breads, pasta, sweets, sodas, etc.) could raise the risk of early puberty through chronic insulin surges. Researchers also believe that high levels of leptin, a satiety hormone produced by body fat and promoted by a high-carbohydrate diet and excess insulin, may contribute to early breast development.


One study found that infants fed soy formula had estrogen levels 13,000 to 22,000 times higher than normal, suggesting that it may play a role in early puberty.

Beef and dairy

The conventional beef industry administers sex hormones to cattle to promote production, greatly raising the levels of hormones in the meat. Milk naturally contains ample estrogen, particularly if the cow is pregnant, and some conventional farms treat dairy cows with hormones to stimulate production. Although the link between meat, milk, and early puberty is controversial and not established, going with products from organic, grass-fed animals is ideal.