Without a doubt, this is an integral part of my fantasies!
Since my fetish began while I was very young it really evolved around the "mystery" of girls as well as the embarrassment/humiliation of intimate exams that all kids relate to. Mostly I've imagined either examining, or just watching (like a fly-on-a-wall) a teenage girl, pubescent or adolescent, totally naive, undergoing a physical exam. While "taking a quick peek" under her panties he lets out a somewhat concerned "Hmmm..." After a short moment-that-last-a-lifetime he (or she, but usually he) confesses that he saw "something" and needs to "just take a closer look down here"...
Or a million variations on the theme...
Over time I have come to realize that what makes these fantasies so powerful isn't the age of the patient, per se, it's the fear of the unknown, the surprise and the embarrassment, and the discomfort of having to voluntarily submit to something so humiliating and/or scary. The age of the patient isn't necessary, but it makes it so much easier to imagine the height of all of those feelings that are so raw and basic, more so than someone who's an adult and understands the way of the world more.
Still, such fantasies always felt so "wrong" and I even wondered, time after time, am I some sort of pedophile? Egads, even now I wonder, although I am coming to better distinguish between fantasy and reality and understand that the thoughts themselves aren't necessarily bad.
-g