Progress in reproductive technologies provided opportunity for scientists to be able to grow human embryos in vitro for more than two decades. Skills and knowledge derived from in vitro fertilization and in vitro culture of mammalian embryos opened the chance for scientists to develop the strategies to derive embryonic stem cell lines from mammalian and human embryos. This achievement has initiated a new era in the fields of biotechnology, pharmacology, basic scientific research and cell-based medicine. To date, scientists have made some progress in optimizing regimens in deriving ES cell lines from human embryos but much more research and development are still required especially in the aspect of directing stem cells into the specific cells of potential clinical use. Collaboration among clinicians and scientists from diverse fields, together with the public awareness of how useful this technology could offer to modern medicine, will result in the accumulation of knowledge in this field and ultimately a progress in cell-based therapy in the future.