There's a short but important discussion here about the ethical and moral implications of using email in the realm of healthcare.

The story is about medical research, but it spreads to any environment where you want some guarantees about senders and recipients. For example, I welcome the idea of being able to talk to my GP or even just my surgery by email, but irrespective of the level of the discussion, I'm not sure I'd want the content to be read by anybody, casually or otherwise.

There are lots of issues here that go beyond the realms of the current technology. For example, it's all very well for me to encrypt the email I send from my computer so that only my doctor can read it, but how do you ensure that it's me sending the mail, and my doctor receiving it?