Both Androgen Insensitivity Syndrome (AIS) and Swyer Syndrone (Pure Gonadal Dysgenesis) are characterized by phenotypical females who are genetic males (46XY). However, The 2 conditions are very different pathogenically and have different clinical implications. For example, AIS patients can not become pregnant; however, Swyer patients may become pregnant after therapy. In this session, we will review the pathogenesis and clinical implications of these 2 46XY conditions.