[Current status of treatment and new aspects of the problems of the undescended testicle (author's transl)].

Early treatment of the undescended testicle was first demanded by Fischer, Bramann and Ramstedt early this century. From the 2nd year of life the number of the spermatogonia decreases rapidly, the diameter of the tubuli decreases, and distension and collaginization of the interstice are revealed by electron microscopy. The descended testis is also injured in unilateral maldescensus. The damage to the undescended testicle seen in the microscopic structure is secondary. Early treatment always begins with choriogonadotropin and only if this is not successful is surgery performed. Treatment with hormones and surgery guarantee normal development of the testicle. The results of follow-up studies show that fertility is favorably influenced by very early treatment.