Bisphenol A (BPA), a chemical that mimics the action of the human hormone estrogen, can leach from polycarbonate plastic. Human exposure to BPA is widespread. A Centers for Disease Control study detected BPA in the urine of 95 percent of adults sampled. Scientists have measured BPA in the blood of pregnant women, in umbilical cord blood and in the placenta, all at levels demonstrated in animals to alter development.
Hormones stimulate certain cancers. Bisphenol A has been found to stimulate prostate cancer cells and causes breast tissue changes in mice that resemble early stages of breast cancer in both mice and humans. One study found an association between ovarian dysfunction and higher levels of BPA in urine.
Early-life exposure to BPA can also cause genetic damage. Researchers found that BPA causes chromosomal errors at low levels of exposure in mice, which can lead to spontaneous miscarriages and birth defects. As for human data, one study found that women with a history of recurrent miscarriages had over threefold higher levels of BPA in their blood compared to women without a miscarriage history.
Of 115 published animal studies, 81 percent found significant effects from even low-level exposure to BPA. While none of the 11 industry-funded studies found significant
effects, over 90 percent of government-funded studies did so.
Adverse effects include:
• Early onset of puberty, and stimulation of mammary gland development in females
• Changes in gender-specific behavior
• Changes in hormones, including decreased testosterone
• Increased prostate size
• Decreased sperm production
• Altered immune function
• Behavioral effects including hyperactivity, increased aggressiveness, impaired learning and other changes in behavior