BPA used to be considered a “weak estrogen” because it binds to the traditional estrogen receptor about 10,000 times less strongly than estrogen does.11 However, we now know that estrogen works through a number of different receptors and pathways. And BPA in fact binds to some of these other receptors and has biological effects with the same potency as estrogen.12 As a result of those findings, BPA can no longer be called a “weak” endocrine disruptor. Hormonal systems are so finely tuned to regulate biological functions throughout the body that even a tiny dose of a chemical such as BPA can cause big problems.