In a case of undescended testis, After what age fuher descent doesnot occur ?

.UNDESCENDED TESTIS * It results from arrest of descent of the testis in some pa along its pathway to the scrotum. * Bilateral undescended testis is called cryptorchidism (means hidden testis). Up to the age of six, microscopic changes are uncommon. After that, testis gradually atrophies, reduces its external as well as internal secretory activity. Eventually, grossly immature epithelial elements with irreversible destructive changes of the germinal epithelium occur. ref:SRB's manual of surgery,ed 5,pg no 1079