system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Is the gift of genius a random phenomenon? If not, what is the purpose?
gpt
Unless you're a believer that there's some sort of Grand Engineer out there that is dictating or influencing our lives and existence according to some aim, not everything has a "purpose". 

Some people are mentally challenged and can't use their brains in the same way as the norm, and some people are brilliant and can use their brains in ways that exceed the norm. It's the way our genetics works, where sometimes we get over-expressed traits such as intelligence and other times they're under-expressed. And the environment the kid is raised in contributes greatly as well. So it's somewhat random, but the odds that two highly intelligent people will have a smart kid is higher than the odds that two normal-intelligent parents will.

Sometimes, as in an idiot savant, those two extremes are combined in one person.