Parents who think that kids today are growing up way too fast may have some scientific evidence to support that view, as well as an unlikely culprit. A study has linked chemicals found in common cosmetics and household products to early onset puberty in girls and, to a lesser extent, in boys.

The study by University of California, Berkeley researchers has linked exposure to what are known as endocrine-disrupting chemicals found in makeup and soaps to earlier development in children. For girls, the early onset was measured in roughly two months; for boys, the average was about a month.

While this may not sound like much, previous research has shown the age at which puberty starts in girls has been getting earlier in recent decades, and scientists have been looking for causes. Earlier puberty brings with it higher risks of mental health problems as well as risk-taking behaviors. Long term, the problems can include a greater chance of breast and ovarian cancer.

The study included more than 300 children and their mothers in California. Urine samples of the pregnant women were analyzed for three of the chemicals that are typically found in personal care products. At age 9, urine samples taken from the children were analyzed, and the children were assessed every nine months from that point to age 13.

The study found higher concentrations of the chemicals in the mothers’ urine was tied to early onset puberty of their children. These chemicals, they said, can mimic or interfere with hormones such as estrogen.

While further study is warranted, the results suggest that parents pay closer attention to the chemicals they put on, as well as in, their bodies every day.