Keith Schillo is professor of biology at the State University of New York, Oneonta. He earned his Ph.D. in endocrinology and reproductive physiology at the University of Wisconsin, and has taught human and animal anatomy and physiology for over 30 years. His writing has appeared in Endocrinology, Biology of Reproduction, Journal of Reproduction and Fertility, the Journal of Animal Science, and Domestic Animal Endocrinology, and he is the author of Reproductive Physiology of Mammals: From Farm to Field and Beyond, from Delmar Cengage Learning.