The infant born with external genitalia that are not clearly male or female is an anatomical, psychological, and social challenge to its parents and to the physicians and nurses who care for the infant and counsel the new parents. A sex assignment must be made promptly, and a plan of management undertaken if the family is to be secure in the community and the child is to have an acceptable role in life. Some time ago, as I studied an infant's chart before calling on the mother and baby, I saw the words, "possible ambiguous genitalia." I realized I could not deal with this anomaly even on an initial basis. Fortunately, the ambiguous structure, an enlarged clitoris, had become normal size. But if it had not, what would I have said to the mother about her baby--even more important, what would she have asked me? This experience prompted me to review the extensive studies on sex anomalies that have been done by Money and others at Johns Hopkins. These studies cast light on the perplexing problems of the child with ambiguous genitalia. The term "hermaphrodite" is de-