How come it’s possible to cryopreserve things like sperm and very young embryos, and to later thaw them out so that they can live, but it’s impossible to do that for older humans or anything that consists of more than a few cells?

Question

I mean, sure, there is mummification and and some bodies being naturally preserved due to coldness or dryness, but I’m talking more about the idea of cryonics- the idea that you could stop a biological organism’s entire metabolism in some kind of suspended animation and then later thaw them out and be able to continue living. Most of this is just science fiction though and greatly exaggerated. All of the people who have gotten their bodies cryopreserved as adults are people who have died and it’s essentially just mummification instead of suspended animation.

In: Biology

Answer 1

The water in mature cells will crystallize while freezing, causing damage to the cell walls and internal bits. The other stuff is just genetic information, and while some tiny amount may be destroyed or corrupted during the freezing process, there is enough that survives to be used as a blueprint to make the bigger stuff.
*embryos get the water swapped out for a fancy antifreeze.