It is not a simple question. I believe it is a mix of both. The willing of becoming a leader comes strongly from the personality, which I believe we were born. But only life, experience, the environment build the final version of the leader. I assume there are events during the leader's life that inspire him/her to make an impact in the lives of other people, to improve something that is not working properly, etc. Now, leaders make other leaders: that I can agree totally. We become better leaders when we have great examples, mentors, who inspire us.