Chemicals affect boys' genital size High levels during moms' pregnancy hurt development, study says May 27, 2005 BY SETH BORENSTEIN KNIGHT RIDDER NEWSPAPERS WASHINGTON -- Baby boys are far more likely to have smaller, less developed genitals if their mothers had high levels of chemicals commonly found in cosmetics, detergents, medicines and plastics, a study released Friday said. The higher the levels of the chemical compound phthalates in the mothers during the final months of pregnancy, the less masculine their boys were when examined by pediatricians, said the study's lead author, Shanna Swan, a professor of reproductive epidemiology at the University of Rochester in New York. "We were able to show, even with a relatively small sample, that phthalate-exposed boys have an increased likelihood of a cluster of genital changes," Swan said Thursday. The infant sons of the high phthalate-level moms had more instances of smaller penises and scrotums and not properly descended testicles, according to the peer-review study published in the journal Environmental Health Perspectives. Boys of highly exposed moms were four to 10 times more likely to have reduced genital development. The most glaring difference between exposed boys was in the anogenital distance, the measurement from the genitals to the anus. In males it is twice the size of females, and a smaller distance has been shown in animal studies to indicate reduced testosterone levels. Nine of the 10 boys exposed to the highest mix of different phthalates had short anogenital distances. Scientists are concerned that these boys might go into puberty late, be infertile and contract testicular cancer because that's what rats with similar reduced anogenital distances showed, said Earl Gray, a senior research biologist at the federal Environmental Protection Agency. The mothers in the federally funded study -- including those with high phthalate levels -- showed similar levels in the range and amounts of the chemicals as the average American, based on previous studies by the federal Centers for Disease Control and Prevention, said study coauthor Antonia Calafat, the CDC's lead research chemist. "If I were pregnant, I would try to keep my phthalate levels low," said study coauthor Christine Ternand, a professor of pediatric endocrinology at the University of Minnesota. "How I would do that would be a tricky thing." Phthalates are used as plasticizers, solvents, coatings and perfume fixatives. They are in hundreds of products, including food packaging, coatings on time-released medicines, soap, shampoo, nail polish, hair sprays, detergents, and vinyl floor coverings. Marian Stanley, a senior director of the American Chemistry Council and spokeswoman for a group of companies that use phthalates, said it was too hard to come to any conclusion from the Swan study, especially since it involved too few people. The study, conducted in Minneapolis, St. Paul, Minn., Columbia, Mo., and Los Angeles, examined 85 infant boys and used urine samples taken from their mothers during the last few months of pregnancy. The National Institutes of Health and the EPA paid for it.