It's a little bit of both. I'm a firm believer in developmental psychology, and that leaders are typically programmed by their parents or other significant influences in their youth. Not programmed to do a specific function, but programmed to have the willingness and open mind it takes to become a leader. The social understanding it requires in order to bring oneself to a position of power above others, the acceptance and respect of the concept of cynicism, self-appreciation and unwillingness to accept defeat are all ideologies which leaders share. Someone who is told that they could never be shit in life, will probably end up not being shit. The ideologies mentioned above are ascertained through believing in oneself. In addition to this, your environment or genetic disposition can have a positive or negative influence on whether or not a person holds these ideologies. Somebody who is born in a very negative environment with a very negative outlook on life, will most likely end up staying there. Somebody who is born to a wealthy family in a positive environment with many opportunities at their disposal, as a far better chance at being a leader. People who have exceedingly high IQ's usually end up being consumed in analytics (cue the "160 IQ child prodigy" who ends up working a government desk job), people who have exceedingly low IQ's usually end up not being able to analyze enough to vet great success. Naturally, people who are more inclined to be narcissistic tend to find it easier to succeed versus people who are compassionate. There are many many factors to consider what it takes to become a leader. I think the most important, though, would be self-perception. If you don't believe in yourself, you won't be leading anyone. This, as explained above, can be a result of the nature of your birth, or how you were raised.