I disagree that I am an "entitled" spoiled brat as you seem to imply. I actually think that it is stupid and entitled to buy more than one can afford (i.e. a new car and a 250k or 300k home on a resident salary). I have never owned a new car, any fancy/designed clothers, or any home or condo. However, being a 33 year old who has worked my entire life, including during college and for several years prior to residency, and having completed a residency already plus a 2 year research fellowship, I would say that wanting to own is reasonable at this point in my life. And I don't think that waiting another 3-5 years until I am pushing 40 and done with a fellowship is necessarily a good thing. Those who rent apartments and houses will charge enough money so that they are making a profit off of me. I would personally rather pay a $800-900/month mortgage than pay someone $950 rent. I disagree that if the home were to not gain in value or go down slightly, I wouldn't be able to pay the money owed when I sold the house...that would assume that I have saved no money during the time I lived in the house, and that I never did any moonlighting, etc. Many people who found themselves "upside down" with regards to their mortages and having to sell bought houses they could not afford to begin with, and had ARMs with shady mortgage companies, or they did not have a secure job situation. I would not consider doing either one of those things. I think your scenario of a home losing 20% of its value is unlikely. It has happened in Florida and California recently, but those prices were way inflated/overvalued to start off with. I personaly wouldn't buy a home or condo that inflated in value.
I agree that folks who have NO money to put down for a down payment or closing costs should probably not buy a home. This would include many or most medical students. However, I would hope that some bank would be willing to lend me money if I can come up with closing costs plus 5-10% of the value of what I want to buy. If a doc with a medical license in 2 states and through-the-roof credit isn't a good risk, I'm not sure who is.