Book excerpt: The authors explore the question of whether our sexual orientation is inherited or if it is a product of our upbringing and/or environment. Many people think gays are born that way, and few understand enough about genetics and human biology to mount a thorough defense of the facts. My Genes Made Me Do It explains the role of genetics and biology in human behavior with a particular, though not exclusive, emphasis on homosexuality. Conventional scientific method and research findings are brought together in a fresh, original way to argue that no human behaviors are biologically determined.