Rapid progress in the development of novel experimental strategies to generate fertile gametes from cryo-preserved ovarian and testicular tissue motivates oncologists to investigate ways in which gonadal tissue might be preserved. Childhood cancer patients remain the major pediatric group which can benefit from these techniques. Other potential candidates include patients with systemic diseases, which require gonadotoxic chemotherapy, patients undergoing gonadectomy, patients with Turner or Kleinefelter's syndrome, and boys with cryptorchid testes. This review aims to present an overview of the current state of knowledge in experimental germ stem cell transplantation in higher primates including humans, and the clinical risks and limitations related to such procedures in children. This area of research is discussed in the context of the potential future options that may become available for preserving fertility in boys and girls.