The question of why some people are attracted to members of their own sex has led to a wide range of answers throughout history. In their attempt to identify the origins of homosexuality, biologists, sociologists, religious leaders, psychologists, and psychiatrists have proposed theories that many people consider absurd. For example, in the eighteenth and nineteenth centuries, medical textbooks claimed that homosexuality was a sign of moral depravity and was caused by demonic possession. Controversial theories explaining the origins of homosexuality have not been consigned to the history books, however. One recent theory, advocated by medical doctors William Wong and Doris Rapp, posits that male babies raised on soy-based formula, instead of milk- based formula or breast milk, may grow up to be gay.

Soy contains compounds called isoflavones (also known as phytoestrogens) that mimic estrogen, the primary female hormone that induces...