In a carefully-controlled study to be published in the April, 2010 issue of the journal Environmental Health Perspectives, researchers from the Columbia Center for Children's Environmental Health (CCCEH) at Columbia University's Mailman School of Public Health found that prenatal exposure to ambient levels of a class of widely-used, flame-retardant chemicals and known endocrine disruptors called polybrominated diphenyl ethers (PBDEs) had adverse neurodevelopmental effects in young children.
You can read an abstract of the paper here: http://ehp03.niehs.nih.gov/article/fetchArticle.action?articleURI=info%3Adoi%2F10.1289%2Fehp.0901340#top
PDBEs are commonly applied to a broad array of textiles and other consumer goods, including mattresses, upholstery, building materials and electronic equipment. Because they are additives not chemically bound to these products, they can be released into the environment. Exposure occurs by dietary ingestion or inhalation of dust containing PDBEs.
According to First Author Julie Herbstman, Ph.D., adverse developmental effects were particularly evident at four years of age, when verbal and full-scale IQ scores were reduced by 5.5 to 8.0 points for those with the highest prenatal exposure. Co-Author Dr. Frederica Perera, CCCEH director and professor of environmental health sciences at the Mailman School, said, "The observed reductions in IQ scores are in the range seeen with low-level lead exposures. These findings could have important public health implications."
To ensure the accuracy and specificity of their results, Columbia's investigators controlled for ten other factors previously linked to neurodevelopmental effects. There's more about their fndings here: http://www.sciencedaily.com/releases/2010/01/100119121434.htm