From the Harvard Business Review:
In my view, the main reason for the uneven management sex ratio is our inability to discern between confidence and competence. That is, because we (people in general) commonly misinterpret displays of confidence as a sign of competence, we are fooled into believing that men are better leaders than women. In other words, when it comes to leadership, the only advantage that men have over women (e.g., from Argentina to Norway and the USA to Japan) is the fact that manifestations of hubris — often masked as charisma or charm — are commonly mistaken for leadership potential, and that these occur much more frequently in men than in women.
This is consistent with the finding that leaderless groups have a natural tendency to elect self-centered, overconfident and narcissistic individuals as leaders, and that these personality characteristics are not equally common in men and women. In line, Freud argued that the psychological process of leadership occurs because a group of people — the followers — have replaced their own narcissistic tendencies with those of the leader, such that their love for the leader is a disguised form of self-love, or a substitute for their inability to love themselves. “Another person’s narcissism”, he said, “has a great attraction for those who have renounced part of their own… as if we envied them for maintaining a blissful state of mind.”