A germ cell tumor that arises from the testis during childhood. The disease is childhood testicular germ cell tumor (Monarch Disease Ontology term MONDO_0003758). Also known as: childhood testicular germ cell neoplasm, paediatric testicular germ cell neoplasm, paediatric testicular germ cell tumour, pediatric testicular germ cell neoplasm, pediatric testicular germ cell tumor, testicular germ cell tumor of childhood, testicular germ cell tumour of childhood.