Plastics may cause birth defects.

• Position: Genetics

Disturbing new evidence suggesting that environmental exposure to a ubiquitous substance may cause chromosomally abnormal pregnancies has been found by researchers at Case Western Reserve University, Cleveland, Ohio. They have discovered that low levels of a compound used in the manufacture of common plastic food and beverage containers and baby bottles interfere with cell division in the eggs of female mice. Disruption of cell division can result in an abnormal number of chromosomes in the eggs, a condition known as aneuploidy, which is the leading cause of mental retardation and birth defects in humans. Down syndrome is an example of a disorder caused by the addition of an extra chromosome.

Patricia Hunt, associate professor of genetics, School of Medicine, is concerned because the compound, called Bisphenol A (BPA), which shows hormone-like properties and mimics the effects of naturally produced estrogens, creates a significant increase in genetic abnormalities at extremely low levels. "Our studies provide the first direct evidence that environmental exposure to BPA acts to disrupt the maturation of the egg and demonstrate a dose-related increase in abnormalities. In addition, they show that, at least in the mouse, exposure to very low doses of BPA within the human exposure range produces detectable effects. These studies raise important questions about the potential impact on human...