What does this mean? “The present study provides the first analytical evidence of the presence of plastic additives with known estrogenic activity in girls with premature thelarche. In a study conducted in 1997 that included 17,077 girls, Herman-Giddens et al. reported that girls in the United States are developing pubertal characteristics at younger ages than previously reported. These authors concluded that the possibility that the increasing use of certain plastics and insecticides that degrade into substances that have estrogen-related physiological effects on living things should be investigated in relation to the earliest onset of puberty.”

While high doses of phthalates do constitute risks in the sense of traditional toxicology, these low doses change the stakes dramatically. Gray's work reveals that male reproductive development is acutely sensitive to some phthalates. For example, the phthalates dibutyl phthalate (DBP) and diethylhexyl phthalate (DEHP) produced dramatic changes in male sexual characteristic when exposure took place in utero, at levels far beneath those of previous toxicological concern. These changes included increases in the rates of hypospadias and other indications of demasculinization. One of the key points is DEHP's impact on developing Sertoli cells, cells in the male reproductive tract that are central to sperm formation. Damaged Sertoli cells during development lead to sperm maladies in adulthood, including low sperm count.

Shortly after the publication of this study, the CDC reported widespread phthalate contamination among adult Americans, but with no companion data on health impacts. The current study (Colon et al.) documents phthalate contamination in a pattern that suggests health impacts. It is restricted geographically to Puerto Rico, and deals with an age cohort different from the CDC’s focus. Taken together, these two studies raise very large red flags for the debate about phthalate safety.

Shortly after the publication of this study, the CDC reported widespread phthalate contamination among adult Americans, but with no companion data on health impacts. The current study (Colon et al.) documents phthalate contamination in a pattern that suggests health impacts. It is restricted geographically to Puerto Rico, and deals with an age cohort different from the CDC’s focus. Taken together, these two studies raise very large red flags for the debate about phthalate safety. Colón et al. are very careful to point out that their study does not prove causation. . The link does not prove causation, but is sufficiently strong to warrant urgent study. Colón, I, D Caro, CJ Bourdony and O Rosario. 2000. Identification of Phthalate Esters in the Serum of Young Puerto Rican Girls with Premature Breast Development. Environmental Health Perspectives 108:895-900.