<p>For me, I wanted to be a doctor since I was three years old. It's been the one overarching constant my entire life. Sociology was an interest that developed in HS after doing a longterm group project. Since I was aware that I didn't need to be bio or chem for medical school, it was easy to pick, and I stayed with Sociology for all four years-never once considering a change. I just made sure I took the appropriate pre-med courses (1 year of bio, gen chem, organic chem, and physics, a smattering of other courses like a year of english, and a semester of calc).</p>
<p>I know that one of my good friends who was PoliSci, didn't decide to go to med school until her junior year of college. I don't remember the precipitating event. Other people were like me and knew that they wanted to go to medical school, but didn't like the idea of a lot of science that wasn't going to be relevant to the process and what they would learn in Med school.</p>
<p>As for the last two questions. Hospitals won't necessarily care that you know alot about politics or econ, but there are positions that the combination of an MD and that knowledge could be valuable. Research into the economics of medicine is hot right now, and a person with such a background would be important for lobbying or research purposes. Hospitals have a lot of political concerns so the same would apply for someone with that background. I've found that my sociology background has helped in understanding patients and their motivations.</p>
<p>As for the astronaut thing: To be a Mission specialist you need at least a college degree, but nearly all MS's have a PhD or MD. You also need at least three years of related experience in that field. The other requirements are physical fitness and "intangibles". What is important to realize is that becoming an astronaut is amazingly difficult. A call for applicants will regularly bring in 10000 applications, of which maybe 400 will be interviewed, and only 20 selected. Astronauts really are those "all-american" type of individuals who are just great at everything they do: very intelligent, athletic, leaders, good communicators, creative, and determined. So yes, being a engineer, but having the people skills to work with many different types of people is a valuable skill set.</p>
<p>EDIT TO ADD: By the by, I was a counselor at Space Camp (Kansas Cosmosphere and Space Center's Future Astronaut Training Program) for a summer, so I do know what I'm talking about as far as astronaut selection goes</p>