system
Given the following post, respond as if you're commenting on Reddit:
human
Genetically Speaking, how many possible people are there? (or how many possible combinations of genes are still "human")

Presumably there would be a lot, but I was wondering what the likelihood of someone having identical DNA to someone who isn't their identical twin. (For example, is it possible for somebody to be born today who is a genetic duplicate of Ghengis Khan or Che Guevara?)
gpt
The human genome has about 4 billion base pairs, of which about 2% are coding. With 80 million things each taking four possible values, the number of combinations is about 10^10^53 possibilities. That's about the square root of googolplex. Obviously this answer is an approximation and ignore other aspects of genetics.