The most exciting prospect for reproductive medicine is undoubtedly the generation of gametes from the infertile patient's own tissue. The moral status of the human embryo is the main point of contention in the ethical debate surrounding human embryonic stem cell (hESC) research. In the scenario in which gametes would be derived from existing stem-cell lines and then used for reproductive purposes, the issue of informed consent needs careful consideration. At present, stem-cell treatments have only proven useful in the treatment of hematologic conditions. For these conditions, however, the alternatives of allogeneic bone-marrow transfer or treatment with cord-blood stem cells are better and cheaper. A final possible application that raises ethical questions is the creation of genetically enhanced children. Pre-supposing that stem cells can be manipulated, this would facilitate germline gene modifications, which faces its own ethical problems and resulting opposition.