Table 1.
Options for fertility preservation and restoration in males.
| Approach | Patients | Future Therapeutic Reproductive Strategies | Fertility Options | Advantage | Limitations |
|---|---|---|---|---|---|
| Cryopreservation of sperm | Adults | ART 1–3 | ART | Fertility preservation | (1) Limited quantity and quality of the sperm (2) Not an option for prepubertal patients since they do not yet generate sperm (3) Not recommended after initiation of chemotherapy |
| Testicular biopsy | Pre-pubertal or Adults | Autologous graft 4−6 Autologous germ cell transplantation 4−6 |
Intercourse or ART | Fertility preservation and/or restoration |
For strategies: (4) Possible contamination with cancer cells * (5) Not yet applicable in human (6) Needs more research for validation, efficiency, and genetic stability (7) Transmissions of mouse virus to human germ line |
| Organ culture 5,6 In-vitro differentiation culture of SSCs to sperm 5,6 Xenograft 5−7 |
ART | ||||
| Induced pluripotent stem cells (iPSC) | Adults | In-vitro culture: Differentiation to SSCs 8,9 |
Intercourse or ART | Fertility restoration | (8) Needs more research for validation, safety, efficiency, and genetic stability (9) Not yet applicable in humans |
| Differentiation of SSCs to sperm 8,9 | ART | ||||
| Agents to protect spermatogenesis | Pre-pubertal or Adults |
Normal fertility 10−12 ART 10−12 |
Intercourse or ART | Fertility preservation | (10) Needs more research for possible protective agents (G-CSF, AS101) (11) Needs more research for validation and safety (12) Not yet applicable in humans |
| Gene therapy ** | Adults Or Pubertal |
Normal fertility 13−15 In-vitro fertilization 13−15 |
Intercourse or ART | Fertility restoration | (13) Needs more research for validation, safety, efficiency, and genetic stability (14) Could be used in testicular somatic cells, but not germ line cells. (15) Not yet applicable in humans |
This table summarizes the different options for male fertility preservation and restoration, and the advantages and limitations of these options. ART—Assisted reproductive technology: Intrauterine sperm insemination (IUI), In-vitro fertilization (IVF), Intracytoplasmic sperm injection (CSI). Fertility preservation—preserves fertility that theoretically should be intact (pre-pubertal) or already approved to be present (adults). Fertility restoration—to restore fertility that does not exist. *—It excludes biopsies from non-cancer patients and cancer patients with non-metastatic tumor. **—Could be performed in vivo or in vitro. Uppercase numbers in column “Future therapeutic” indicate the types of limitations. The numbers in column “Future Therapeutic Reproductive Strategies” indicate the type of limitation in the column “limitation”.