No-one should be surprised by the plausibility of rejuvenation biotechnology, as old people create young children, and only a tiny hint of the damage that makes people old seeps through that process. So we know that there exist ways for cells and larger structures to extremely effectively manage their level of damage - and some of the explorers in stem cell science have already recreated these processes outside their normal context. Here is a further exploration of what happens when old animals create young animals: "Although the body is constantly replacing cells and cell constituents, damage and imperfections accumulate over time. Cleanup efforts are saved for when it really matters. ... I have a daughter. She is made of my cells yet has much less cellular damage than my cells. Why didn't she inherit my cells including the damaged proteins? That's the process I'm interested in. ... A few days after conception, the cells in the embryo all look the same - they are unspecified stem cells that can develop into any bodily cell type. As the process of cell specification (differentiation) begins, they go from being able to keep dividing infinitely to being able to do so only a limited number of times. This is when they start cleansing themselves. ... Quite unexpectedly we found that the level of protein damage was relatively high in the embryo's unspecified cells, but then it decreased dramatically. A few days after the onset of cell differentiation, the protein damage level had gone down by 80-90 percent. We think this is a result of the damaged material being broken down. ... In the past, researchers have believed that the body keeps cells involved in reproduction isolated and protected from damage. Now it has been shown that these types of cells go through a rejuvenation process that rids them of the inherited damage." Can this process be isolated and applied safely to ordinary cells elsewhere in the body? Time will tell, but it's a worthy goal to aim for given its demonstrated effectiveness.