system
Given the following post, respond as if you're commenting on Reddit:
human
If telomeres shorten at each cell division, how come each successive generation doesn't have shorter telomeres?

I've heard that telomeres shorten with each cell division, and that this is one of the processes involved in ageing. But for example in humans, a child's cells all are the result of cell division starting from a single cell, which in turn comes from the two gametes of its parents. These gametes are themselves the result of a chain of cell divisions in the parents. So the further you advance in the "generations" axis, the longer these "chains of cell division". So, how come it's not the case that each generation has shorter telomeres than the one before it?

More generally: a child's cells ultimately come from its parents' cells, and ageing roughly consists of cell damage accumulated over time; so how come the state of ageing isn't transmitted from parent to child, but is instead "reset" every time reproduction happens?

I'm having a hard time writing my thoughts in words, but I hope you understand what I mean.
gpt
Telomerase. It’s an enzyme that lengthens telomeres. It’s produced in certain cells at certain times to maintain telomere length. Some cancers also have telomerase active, so can escape that mode of cellular death.