From Singularity Hub: "Hans Keirstead used embryonic stem cells to help paralyzed rats walk again. His research is the basis for the first FDA approved clinical trial for the use of embryonic stem cells (ESC) - currently underway by Geron and aimed at treating spinal cord injuries. After years of controversy in the first part of the decade, ESC trials have finally started on the path that may let them deliver on the vast promises of stem cell enabled medicine. Yet we have already seen how autologous stem cell therapies (those which use a patient's own cells) are becoming available in the U.S and all over the world. Why the hold up on ESC treatments? Autologous therapies are part of the medical practice of individual doctors, given to their individual patients. Geron's clinical trials hope to usher in a new wave of globally used drugs and procedures. The rigorous science needed to obtain FDA approval for such widespread treatments is not easily achieved, but many still lament the slow process. To all of us wondering why ESCs are not yet available in every hospital across the world, Hans Keirstead has an explanation. He doesn’t make an impassioned plea, or take a rhetorically defensive stance. In just 5 minutes Keirstead walks us through the fundamental hurdles that scientists face as they try to bring ESC therapies to fruition. Everyone who wants an intellectual and scientific explanation of stem cell research should watch the video."