Ethical issues with regard to transplantation of cord blood stem cellsAbstract. Definition of the problem: Cord blood banks have been and are still being set up in many modern states all over the world. Cord blood transplantation, however, gives rise to a specific set of ethical problems, that must be cleared up and analyzed before full responsibility can be assumed and the establishment of banks for frozen cord blood samples and the structural implementation of cord blood transplantation can be justified. The main ethical issues concerning cord blood stem cell transplantation can be divided into at least six groups of questions that are closely related. First, there are ethical issues concerning the status of the treatment. Must cord blood transplantation somehow still be considered an "investigational" treatment or can it be regarded as accepted therapy? Second, we must face the question of the ownership of the placental tissue. Third, there are questions regarding the fairness in the collection and distribution of cord blood. Fourth, there is the issue of informed consent. Fifth, there is the question of whether how new data from medical testing will be communicated to the parents or the donor. Finally, questions related to privacy and confidentiality need to be addressed. Conclusion: As it is likely in the years to come that the supply and demand for cord blood will grow, clinicians will increasingly need answers to these ethical questions. Only thoughtful analysis of the attendant ethical issues of the establishment of banks for frozen blood samples and the structural implementation of cord blood transplantation can mitigate potential problems.