If we assume that String Theory (ST) gives a good description then the question is related to the https://en.wikipedia.org/wiki/String_theory_landscape The number of theoretically allowed vacua (universes) is extremely large and that is one of the arguments against ST; the issue is to find ways to exclude as many as possible and to find relationships between different parameters so even more are excluded.
If this can be done and if we end up with only one universe then we are done. If there are more than one then there are different possible universes and then the question arise which of the suggested vacua that can give rise to life. The mathematics in ST is quite hard, so it will take some time until there is a solution. That is an argument against studying ST, there are many other areas to study with a better probability to get something interesting.
Sheldon: Penny, while I subscribe to the “Many Worlds” theory which posits the existence of an infinite number of Sheldons in an infinite number of universes, I assure you that in none of them am I dancing.
Penny: Are you fun in any of them?
Sheldon: The math would suggest that in a few of them I’m a clown made of candy, but I don’t dance.