The new study, in establishing the potential harmful effects of prenatal exposures, provides a possible method of screening populations to detect signs of arsenic contamination. Moreover, it is the first study to provide evidence of genome-wide changes resulting from prenatal exposure from any environmental contaminant. In a collaborative study, researchers at the Chulabhorn Research Institute (CRI) in Thailand and of the Massachusetts Institute of Technology (MIT) in the United States have found that the children of mothers exposed to water supplies contaminated with arsenic during their pregnancies showed gene expression changes that could lead to cancer and other diseases later in life, even if the children themselves were never directly exposed to arsenic. The new study, in establishing the potential harmful effects of prenatal exposures, provides a possible method of screening populations to detect signs of arsenic contamination. Moreover, it is the first study to provide evidence of genome-wide changes resulting from prenatal exposure from any environmental contaminant. Arsenic contamination is a health concern worldwide with millions exposed to levels that exceed the World Health Organization (WHO) safety standard of 10 parts per billion (ppb). The element was classified as a Group 1 carcinogen by the International Agency for Research on Cancer (IARC) and has been implicated in such diseases as vascular disorders and diabetes. The CRI research team included...