AR and complete androgen insensitivity syndrome: To establish the role of AR in the adult Leydig cell lineage, we generated a novel mouse model in which AR is ablated from ∼75% of adult Leydig stem cell/cell progenitors, from fetal life onward (LCARKO mice), permitting interrogation of the specific roles of autocrine Leydig cell AR signaling through comparison to adjacent AR-retaining Leydig cells, testes from littermate controls, and to normal human testes and those from patients with complete androgen insensitivity syndrome (CAIS), arising through mutation of AR.