Testicular Tissue Cryopreservation in Prepubertal Boys: Current Advances, Clinical Feasibility, and Future Directions—A Comprehensive Literature Review

BACKGROUND: Prepubertal boys cannot use semen cryopreservation because mature spermatozoa are not yet produced. Testicular tissue cryopreservation (TTC) is therefore offered to selected high-risk patients as an experimental fertility-preservation procedure that stores spermatogonia and their supporting niche for potential future use. OBJECTIVE: To integrate the TTC pathway from patient selection and tissue banking through follow-up, fertility restoration, and oncologic safety, while reassessing translational readiness in light of recent first-in-human evidence. METHODS: A structured narrative review of 49 publications was conducted using literature updated through August 15, 2026. PubMed was supplemented by targeted journal, publisher, preprint, and reference-list searches. Original human evidence was prioritized, with first-in-human reports classified according to the highest endpoint demonstrated. RESULTS: More than 3000 patients younger than 18 years have undergone TTC internationally, with contemporary cohorts reporting low short-term morbidity and no clinically meaningful treatment delay in appropriately selected patients. Tissue quality may be affected by disease and prior gonadotoxic exposure. First-in-human autologous transplantation of cryopreserved immature testicular tissue demonstrated graft survival, revascularization, complete intragraft spermatogenesis, and rare sperm recovery. Autologous transplantation of cryopreserved testicular cells demonstrated feasible rete-testis delivery without restoration of spermatogenesis at 1 year. Patient-specific germline regeneration has also reached the human primordial germ cell-like cell stage. Malignant contamination remains a major concern, particularly in hematologic malignancies. CONCLUSIONS: TTC has entered an early human translational phase but remains investigational. The key challenge is now to achieve reproducible, clinically usable sperm production with proven fertilization competence, healthy live birth, and offspring safety.