In this review, we will evaluate preoperative variables such as age, FSH, testicular volume, inhibin B, genetics, Klinefelter syndrome, history of varicocele, cryptorchidism, as well as intraoperative variables such as histopathology and tubular diameter and their relevance for predicting the outcome of micro-TESE. The gene discussed is BRD2; the disease is cryptorchidism.