How should we classify intersex disorders?

The term disorders of sex development (DSD) has achieved widespread acceptance as replacement for the term intersex, but how to classify these conditions remains problematic. The LWPES-ESPE (Lawson Wilkins Pediatric Endocrine Society and European Society of Paediatric Endocrinology) Consensus Group proposed using the karyotype as a basis for classification; however, this is but a crude reflection of the genetic makeup, is diagnostically non-specific, and is not in itself relevant to subsequent clinical developments. The historical classification of intersex disorders based on gonadal histology is currently out of favor, being tainted by association with the terms hermaphroditism and pseudohermaphroditism. We believe this is regrettable, for the histology of the gonad remains fundamental to the understanding of normal and aberrant sexual development by medical students and residents in training, as well as being a major determinant of clinical outcome for the patient. We propose a comprehensive classification of those DSD conditions generally regarded as belonging under the heading of intersex, based on gonadal histology. Biopsy will not be required when the diagnosis is clearly established biochemically or by gene studies as the histology can be confidently predicted. It will only be required when an ovotestis or dysgenetic gonad is suspected in order to determine the definitive diagnosis.