Exposure to chemicals found in a wide array of personal care products has been linked to early puberty among girls. The author of the study from U.C. Berkley Kim Harley, PhD. says specific chemicals including phthalates, parabens and phenols, have been found in certain laboratory conditions to mimic estrogen once they are ingested in a girl’s body. The chemicals are found in common grooming products, including perfumes, soaps, shampoos, nail polish, cosmetics, toothpaste, lipstick, hairsprays and skin lotions - to name just a few.
In fact, prior animal studies have suggested that exposure can throw puberty timing out of whack, Harley said. Her team found that "the higher the levels of the chemicals in mothers' or daughters' bodies, the earlier the puberty" among girls. No such link was found for the timing of male puberty, however.