Spermatogonial Stem Cell (SSC) Transplant and Testicular Tissue Grafting

This study offers a chance for men who had their testicular tissue frozen before cancer treatment (such as chemotherapy or radiation) to have that tissue transplanted back into their body. The goal is to help restore fertility that may have been lost due to cancer treatment. **You may be eligible if:** - You are male and have gone through at least the early stages of puberty (Tanner stage 3 or above) - You previously had testicular tissue or cells frozen because your cancer diagnosis or treatment put your fertility at risk - You are healthy enough to undergo anesthesia - Your cancer doctor has confirmed you have finished treatment and are cleared for this procedure **You may NOT be eligible if:** - You are considered high-risk for surgical complications - You have a history of leukemia, lymphoma, testicular cancer, or another cancer that may have spread to the testicles at the time tissue was collected - You have a psychological or psychiatric condition that prevents you from giving informed consent Talk to your doctor to see if this trial is right for you.