I'm up to the part of "Ageless" where he discusses the cell by cell damage
- DNA copy errors
- DNA hit by cosmic rays
- cellular trash that can't be removed
And the ideas to do genetic therapy to fix the DNA. Except, think, this is like having a different genetic disease in each cell. So in cell one you need to cure Huntington's, in cell 2, Cystic fibrosis, and so on.
Turning a cell into a baby reboots the DNA "computer" & resets all the cells.