In an exclusive interview on June 6, 2011 with Dr. Rudolf Jaenisch, a professor of biology at the Massachusetts Institute of Technology and a founding member of the Whitehead Institute, Dr. Jaenisch discusses the current advancements in cellular reprogramming. In the first of a three part series, Dr. Jaenisch talks about the advantages of mRNA reprogramming and the future challenges of using iPS cells in the field of stem cell research.