BRD2 and cryptorchidism: The presence of Ad spermatogonia in the undescended testis influences the levels of FSH, and in patients with unilateral cryptorchidism the presence of Ad spermatogonia in the contralateral descended testis is a dominant predictor for the fertility outcome, since in boys with unilateral cryptorchidism, testicular pathology caused by hormonal imbalance is bilateral; 71% of scrotal testes have a reduced number of germ cells and 75% have impaired gonocytes transformation into Ad spermatogonia [34].