They put the viewer on a bit of a roller-coaster ride with segments
about some new research or discovery with fantastic potential, then
tempering our enthusiasm with the downside (example: we might be able to
change our "clock" genes but the free radicals will get us anyway).
They ended off with finding a way to make our cells renew themselves
indefinately so as to avoid free radical damage. Though they suggest
this is possible, apparently the cell reproduction goes out of control,
inevitably leading to cancer. And then you die.
I don't follow their logic however: If the point of cell renewal is to
replace damaged cells, and our red blood cells (for instance) can do
this more rapidly than cells in other parts of our body, why couldn't we
make these other cells work at least as well (once we find the way to
reprogram them) and keep their reproduction stable as that of the red