I've had two female doctors examine me before. One was filling in the place when my regular doctor was not available. She was in her early 30s, I believe, and gave me a full physical examination so she therefore saw me fully naked. The other one was maybe late 40s, early 50s and looked at an itchy rash I had around my anus(never really figured out what caused that). I was comfortable with both of them so I wouldn't have any reservation about a female nurse being in the room as well.