HIPPA Health Information Privacy Protection Act makes it unlawful for any medical information, any responses to any questions, anything, in process of a Doctor's care giving, to be used outside of the medical field. The regulations are so tight caregivers are not allowed to discuss medical details with each other on a medical staff legally except in the performance of their job duties.
Umm, yes, and no. Doctors are required in most areas to report suspected abuse or neglect to CPS, with no clear legal definitions on what constitutes such. While the information obviously wasn't used this way in this case, it is not a stretch to envision a militant anti-gun doctor lidging allegations of abuse/neglect against a parent whose child reported them for gun ownership.
The truth is, we HAVE become everything we hated about Nazi Germany and Soviet Russia in too many ways. In George Bush's America, it is not inconceivable that a dissident could be whisked away in the middle of the night (Gitmo, anyone? All we have to do is label them a "terrorist, and bingo! Civil rights go *poof*!), and the government goes on TV BEGGING citizens to turn in their neighbours for even the suspicion of wrongdoing (most notably in the areas of CPS/Domestic "terrorism"). Governments try to indoctrinate children in the schools and undermine private faith, almost to the point of ridiculing it. We've got a long way to go before it is truly as bad as it was in those nations, but we're on the right highway, with a full tank of gas.