Somatic Cell Nuclear Transfer–Derived Embryonic Stem Cell Lines in Humans: Pros and Cons

Abstract The recent paper, published by Mitalipov's group in Cell (Tachibana et al., 2013), reporting the production of human somatic cell nuclear transfer (SCNT) embryonic stem cells (ESCs), opens again the debate if, in the era of induced pluripotent stem cells (iPSCs), the production of these cells is indeed necessary and, if so, whether they are different from ESCs produced from spare embryos and iPSCs. It is our opinion that these questions are very difficult to answer because it is still unclear whether and how normal ESCs differ from iPSCs.