Naked Attraction

The blaring wail of air raid sirens fills the night sky. Judson, a middle-aged sergeant in the Air Force, is deployed in the Middle East during the Iraq war. He reflects on life with his wife, grown children and the root of his traumatic evangelical experience which hindered his thinking for years and inspired his memoir "No More Secrets: Sucked in and Spit Out."

From the sea horse that mates in an hypnotic underwater ballet to the rodent who copulates until he literally drops dead, THE NATURE OF SEX spans the globe to illustrate how an astonishing diversity of life forms find their mates and conceive, raise, and protect their offspring. This Web companion to the four-part series takes a close look at the primal instinct that causes animals to come together in order to pass along their genes to the next generation.