In just the last six months, scientists have made noticeable progress in understanding what makes stem cells tick. Biochemical mechanisms are uncovered, and in this article from Betterhumans, ways to efficiently control cell differentiation are explored. This particular advance is a clever and useful one. By introducing a mechanism to lengthen cell telomeres at the right time, researchers can create immortal progenitor cells that continually divide to create an endless supply of the desired cell type (spinal neurons in this case). There are uncertainties in the technique, especially relating to cancer in immortal cell populations, but this looks like it could be a powerful new addition to the early-stage regenerative medicine toolbox.