In recent years, scientists have proposed that chemicals released into the environment may be disrupting the endocrine system of humans and wildlife. The endocrine system is a network of glands and hormones that regulates many of the body's functions, such as growth, development, behavior, and maturation. The endocrine glands include the pituitary, thyroid, adrenal, thymus, pancreas, and the male and female gonads (testes and ovaries). These glands secrete regulated amounts of hormones into the bloodstream, where they act as chemical messengers as they are carried throughout the body to control and regulate many the body's functions. The hormones bind to specific cell sites called receptors. By binding to the receptors, the hormones trigger various responses in the tissues that contain the receptors.

An endocrine disruptor is an external agent that interferes in some way with the role of the hormones in the body. The agent might...