If the introduction of more stem cells helps when you're aged and injured, could it also help you push off age-related degeneration, or otherwise improve the duration of some youthful capacities? The profit motive in professional sports seems the most likely way to answer that open question, given that enhancement (and even prevention, all too often) isn't on the regulatory agenda for mainstream medical research funding. "There's a spin-off technology from stem cells that could produce super-athletes ... injecting stem cells into healthy muscles might increase their size and even restore them to their youthful capacity. ... You could potentially find a 40-year-old man with 20-year-old legs." Sadly, there's all to much to aging that you can't fight with forms of regenerative medicine or enhancement via boosting stem cell activity - if such proves plausible. That shouldn't stop us from trying for those gains that can be had.