person who grew up in large family generally may have better social skills than someone from a small family. This is, in a way, true for cats, too. Every cat is part of a litter of several kittens, and the general rule is that the longer a kitten stays with his littermates, the more tolerant he is of other cats while growing up.
None of this information is very important if you own only one cat and don’t want another. But if you’re thinking of having two or more cats in your home, it might be useful to learn about the “adolescence” of the cat you are thinking of taking in.