I have two college friends who are now full-blown specialist doctors (one orthopedic from UCSD and another psychiatrist graduated from JHU). Both of them came from well-off backgrounds (in fact, both of them have at least one parent who is a doctor). Their parents helped them connect with practicing doctors in famous hospitals (e.g., children hospital of Philly) when they were in college, and both of these friends already had a handful of internship/externship experiences at credible hospitals when they graduate from college.

The psychiatrist friend even took one year off to study for USMLE step 2 before she applied to med school. Who can afford this kind of luxury? It's simply because her parents are both doctors (one psychiatrist and one anesthesiologist) and make a total of easily 600K/year back in 2009.

In comparison, while she (my friend) was studying for USMLE step 2, I was frantically looking for a job in 2009 after graduating from college (the same class year as her).

If one does a bit of research on doctors, one may likely find a positive correlation with their parents being wealthy (and also being one of their parents being a doctor). To become a doctor, one has to be born in a truly middle-class family (like parents earning at least 200K/year total with nowadays dollar kind of middle class).