AR and complete androgen insensitivity syndrome: The LCARKO mouse model with its normal T levels and lack of functioning AR is reminiscent of CAIS in humans (normal/high T; no AR), unlike the Tfm or ARKO mouse, which has low T levels and absent steroidogenesis, and because we have recently identified that adult Leydig cells arise from the same stem cell population in both mice and humans (16), we assayed for apoptosis in testicular biopsies of patients with CAIS at different ages.