Low chemical exposure may speed male puberty.

A recent much-publicized study highlighted the adverse effects that prenatal exposure to chemicals known as phthalates has on the genital development of male infants. Population Council biomedical researchers are now studying the effect of prepubertal exposure to these chemicals on the onset of male puberty. They have found that exposure to low levels of the chemicals can alter levels of a number of sex hormones increase the proliferation of cells in the testes and significantly accelerate the onset of puberty. Phthalates are chemicals used to make plastics—such as those used in food packaging and infant toys—more flexible. They are also used as stabilizers in many common cosmetic products such as nail polish shampoo and lotion. Because they are used so widely exposure to these chemicals is difficult to avoid. In fact a recent study by the U.S. Centers for Disease Control and Prevention (CDC) found low but relatively widespread exposure to phthalates among the U.S. population. Levels of 11 of the 12 phthalates for which the CDC tested were higher in children than adults. (excerpt)