Just to be clear, and I'm not saying you said that I said that (uh...), I'm pretty sure that the vast majority of doctors are not in the profession for this reason (a reasonably large part of my family and friends are doctors, all of them fine professionals with nothing but the best intentions in mind). So just to make clear that I'm not hammering on doctors here :)
That said, OK let's take away the consent. Let's say you're under anesthesia for removing your sinuses and the doctor pulls up the blanket and performs a genital exam. I still hold that this is not sexual assault.
(Note that this is not a hypothetical example. It is fairly common practice in Dutch hospitals for interns to practice gynecological exams on women on the surgery table, even without these women knowing. 4 or 5 students literally line up for this practice. There was a minor fuss about it a few years ago, maybe standards have been changed since then. The references I can find about it date from 2005-2006 and are all in Dutch. The doctors back then thought it was normal and nothing to be up in arms about. I have no reason to believe doctors in other countries have different methods; after all, otherwise where are these students going to practice? ).