Makeup, toothpaste, and soap: What do these everyday personal care items have in common? According to a recent study, certain chemicals found in them could contribute to girls hitting puberty earlier.

The study, which was led by researchers at the University of California Berkeley and published in the journal Human Reproduction earlier this week, analyzed pregnant women who lived in “farm-working, primarily Latino communities of Central California’s Salinas Valley” between 1999 and 2000, according to a news release from UC Berkeley.

Researchers took urine samples from mothers twice during their pregnancy. They then took urine samples from the 338 children — 159 boys and 179 girls — when they reached 9 years of age, then tracked their growth and “developmental milestones” from that time until they reached age 13.

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The urine was tested for the presence of different chemicals, such as diethyl phthalate and triclosan — the first of which “is often used as a stabilizer in fragrances and cosmetics,” according to the news release. The second is found in some kinds of toothpaste.

By the end, “researchers in the School of Public Health found that daughters of mothers who had higher levels of diethyl phthalate and triclosan in their bodies during pregnancy experienced puberty at younger ages,” they concluded. The same was not true for boys.

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But this study is one of the few that has specifically analyzed how these chemicals could affect “the growth of human children,” researchers said.

While it’s not absolutely certain the chemicals were causing the girls to reach puberty at a younger age, “people should be aware that there are chemicals in personal care products that may be disrupting the hormones in our bodies,” Harley said, adding more research is still needed.