Typically, if I'm instructed to undress, it's by the nurse that brings me back to the exam room after she finishes doing the preliminary checks and asking me questions. However, I have a broad spectrum of experiences at the various doctors I've been to. I've been fully clothed for an exam with no skin being exposed at all, to being in only my underwear and those being lowered to my ankles at the end.
At the female pediatrician for yearly check-ups or for an illness. The nurse leads me back to an exam room, has me remove my shoes, checks my weight, takes my temperature, and verifies why I'm there. As she's leaving the room she would tell me, "Take your shirt off and have a seat on the table. Dr. J will be in soon." After a small wait the doctor comes in and starts the exam after a brief discussion with my mother in the room. Towards the end I'm instructed to lie down and she does the abdominal exam. Next she would un-fasten my pants herself and feel around just inside my underwear. She'd finish and have me sit up. I remember she'd never tell me we were done or to get dressed. So I'd just sit there on the table without a shirt on and my pants pushed down a bit hanging wide open.
At the same female pediatrician for a sports physical. The nurse leads me back to an exam room, has me remove my shoes, checks my weight, takes my temperature, and verifies why I'm there. As she's leaving the room she would tell me, "Get undressed and have a seat on the table. Dr. J will be in soon. You can leave your underwear on though." The doctor came in, immediately started her exam, and everything was the same as before. However, at the end while I'm lying down, she raises my underwear with one hand and feels all along my scrotum with the other. She does this on both sides, then she just pulls my underwear out and down past my genitals and does a visual exam.
At a male doctor for a sports physical. Nurse brings me back and does preliminaries in the hall. Once in the exam room she says, "Strip down to your underwear and have a seat on the table", as she leaves shutting the door. Entire exam I was in my tighty whities until the end when I was instructed to stand on the step at the end of the table and drop my shorts for the hernia exam.
At my male dermatologist. Nurse takes me back and does preliminaries in the hall before leading me to the exam room. Once inside she asks me questions, goes over a few things, and verifies that I'm there for a full body skin exam. She pulls a cloth gown out of a drawer on the side of the table and tells me, "Take everything off. Put the gown on, opening in the back. Don't bother tying it, the doctor will start on your back. When you're done changing, open the door a little so we know you're ready. The doctor and I will be back in a few minutes." During the exam the gown gets lowered, folded, and raised. They do an excellent job of seeing nearly every square inch of my skin without me feeling too exposed.
At male urologist for vasectomy consultation. He just had me lower my pants and underwear to mid thighs for a genital exam while lying down.
At my previous female PCP for annual check-ups. I never removed a single article of clothing. She examined me fully clothed, never did genital, rectal, checked my skin, or anything of that nature.
At my current male PCP for new patient physical exam. I remained fully clothed during the exam. I just raised my shirt when needed and lowered my pants and underwear for genital, hernia, and prostate exam. I have a feeling however that in future exams the nurse will have me undress to some degree. After taking my weight in the hall and doing preliminaries in the exam room she asked if I asked if I was there for a physical. Before she left however she said, "I'll just keep you in those clothes. Besides, nobody wants to meet the doctor naked."