system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why is it that we can use cryogenics to freeze sperm and eggs, and upon thawing they reanimate but we cannot do the same with humans?
gpt
The problem lies in the amount of time it takes to freeze and thaw.  If you could instantly freeze something as large as a typical human, then instantly thaw it later, theoretically they would resume life as if nothing had happened.  Assuming the freezing process itself didn't cause damage.  We're mostly water, though, and water expands and contracts as temperatures change.  That's why steam power is a thing.

The process of freezing a large mass is slow and generally damaging.  The thawing process is slow as well, so you will have a period of time where frozen bits and non frozen bits are trying to coexist, and frozen water is sharp crystals that damage soft things like most of our important bits.

Individual cells are small enough to freeze and thaw quickly enough to avoid these problems.