RecruitingDrug trialProspective Observational Study of Outcomes After Gemcitabine, Docetaxel, Melphalan, and Carboplatin With Autologous Stem Cell Transplantation in Pediatric Relapsed/Refractory Germ Cell TumorsTo collect information about treatment outcomes in pediatric and adolescent patients with relapsed/refractory germ cells tumors who receive GemDMC with an ASCT.