Only Individuals are leaders. No single profession (Teachers, Doctors, Lawyers, etc) can claim a total population of leaders. There are teachers that lead and teachers that do not. We've all had examples of both. It is the individual, regardless of station, that provides leadership.
This doesn't mean that all professions offer the same opportunities for leadership.
Some careers, business comes to mind, REQUIRE leadership for success. A successful businessman is someone who creates a plan for a group and then organizises/motivates them to follow it. In other words, leadership. Similar examples include social workers, politicians, policy analysits, anyone in finance, etc.
Some professions offer opportunities for leadership, but don't require it if you don't want it. Medicine, law, and teaching seem like excellent examples. You can certainly spend you time trying to organize your colleagues and community,, but you can also succeed as an individual professional selling his/her services.
And some professions don't particularly lend themselves to leadership even if you want it. In science and engineering, for example, most companies have a set up that the management side of things provides the leadership and even senior engineering professionals just provide estimates of feasibility for management objectives and then do the work (I know this isn't the case at all firms). Of course, the engineers can move on to the management side of things, but then they're not really engineers anymore.
Of course whille I lump medicine into the 'leadership optional' category, I think it varies by residency. There are a few fields, such as infectious diseases, which more or less require leadership if you want any sort of positive outcome for your patient population. On the other hand I don't many ways a plastic surgeon would be a leader with the possible exception of within his/her own professional organizations. For primary care I think it gets even more complicated: with hospitalists having relatively few chances to lead major community based interventions (except when they're pretty high up the hospital food chain) and small town doctors having the chance to be leaders in the Community's health issues right away.
Now this doesn't mean that anyone can't be a leader in their community in their spare time. You can do that whether you're a CEO or a garbage man. However I think the OP was asking whether doctors are leaders when they're on the clock. The opprtunity will always be there for those that want them, but depending on your preferences and specialty the answer might be no.
