Currently, cell replacement therapies using allogeneic hESCs has been thwarted by the host immune response, which can only be overcome by administering long-term immunosuppressive drug therapy. However, the generation of patient-specific hNT-ESC lines (NT-ESCs) is a strategy that may circumvent immunorejection. This autologous approach has been circulating in the scientific and media circles since the late nineties. However, until recently was restricted to discussions relating to ethical concerns and potential benefits^{1, 2}. Nuclear transfer (NT) is an embryo technology that has been used for the purposes of reproductive cloning and more recently for therapeutic cloning³. In 2004, the realization that hESCs of genetic origin to patients may indeed be possible arose following the report of a patient-specific ESC line produced from a human NT blastocyst, although this was recently shown to be fraudulent following external review and the paper was retracted from publication, along with a later publication claiming the production of eleven patient-specific NT-ESCs. It is regret that these papers were retracted as they had brought the concept, therapeutic cloning, closer to reality. However, other researchers are actively pursuing the generation of NT-ESCs as an alternate source of cells for cell replacement therapies. The implications of the retracted papers on the field of therapeutic cloning and ESC research at such an early stage is unknown. Continuing negative media and public response could be detrimental to this field of research and lead to financial withdrawals and/or lack of funding opportunities, although it is hoped that more positive opportunities may arise. The development of autologous ESCs, which are genetically identical to patients suffering from currently incurable diseases, may provide alternate clinical treatments. Patient-specific hNT-ESCs could be derived from NT blastocysts, which are produced following fusion of a single donor cell from a patient into an enucleated oocyte supplied by a female donor (Fig. 1). Embryonic stem cells (ESCs) have the capacity to self-renew and remain in a pluripotent cell state, but also may differentiate into cells representative of the three embryonic germ layers, endoderm, mesoderm and ectoderm, in the presence of varying physical and biochemically inducing factors. Their characterization, culture and applicability for cell replacement therapy has been well documented^4-6. This review highlights the progression and development of NT-ESCs in both animal models and in the human. An emerging controversy over the use of NT blastocysts, which contain a heteroplasmic source of mitochondria and which may also harbour altered genetic profiles as a consequence of incorrect nuclear reprogramming is also raised. Moreover, the current ethical climate and current policies are discussed and how they limit and direct current as well as future research. In light of the ethical concerns, a number of alternative strategies propose to bioengineer cells without necessity of sacrificing early stage human embryos. The potential and limitations of these strategies are discussed.