Untangling the Gordian Knot of Human Sexuality: What Is the Biologic Basis of Variations in Sexual Phenotype?

There is increasing interest in and tolerance of the lay public for variations in human sexuality. In contrast, the molecular biology that underlies gender identity, the development of gonadal and genital anatomy, and the factors that define sexual behavior is proving unexpectedly complex and is still incompletely understood. It is now evident that humans cannot be characterized as member of 1 of 2 clearly defined units: male or female. In fact, individuals exist on a continuum: those who do not conform unequivocally to the dyadic view of human sex in terms of anatomy, gender identity, and/or sexual behavior should be characterized as having variations in rather than disorders of sexual development. Such individuals can no longer be regarded as anomalies to be rejected, condemned, and, if possible, “corrected” either psychologically or anatomically