Introduction 46,XY XR disorder with defect in androgen receptor results in normal-appearing female with male genotype Loss of negative feedback results in ↑ testosterone and LH ↑ estrogen due to conversion of excess testosterone via aromatase Y chromosome contains the sex determining region of Y (SRY) encodes the gene for Müllerian Inhibitory Factor (MIF) produced by Sertoli cells results in degeneration of internal female sex organs promotes testosterone expression Lack of DHT effect (due to defective receptor) results in no external male sex organs Presentation Physical exam rudimentary vagina presents with no sexual hair cryptorchid testes often found in labia majora or inguinal canal surgically removed to prevent malignancy