Affected XY individuals have infantile unambiguous male external genitalia, and male wolffian ducts and lack miillerian ducts. There are, however, no detectable testes. Early testis function did occur (wolffian presence, AMH function) but was not sustained in sufficient amounts or duration to develop a normal size phallus. It is frequently called "the disappearing testis syndrome. Sex of assignment depends on the extent of external genitalia development.