I love the intelligent discussion this topic has generated here. Great first post, Natalie!
My own experiences which brought me to Medfet were mostly school physicals, which are the first physicals I can really remember despite having physicals with our family doctor for years before. I think it was the fact that these physicals were with professionals I had never met before, each year was a different doctor, always a female, that made this very different than physicals with our family doctor, who did my physicals since before I can remember. So, being asked to undress in front of, and then be almost or totally naked in front of these people was very different than anything I'd ever done before.
Those school physicals ended after only three years, when I was probably 8 years old. Then, I just had physicals with the family doctor, which I only slightly consider much of a contribution to my interest in Medfet, at least until I reached puberty and began to have much greater sexual awareness. But, that doctor and his staff were so familiar to me, those physicals didn't really have that sort of excitement for me.
When our family doctor retired, I was about 17, and our family started going to a small local medical practice which had three or four doctors and a changing staff of nurses, assistants, and med students. That was when, with my hormones much more active, I began to feel more excitement around medical visits. Again, part of it was often having someone different seeing me at each physical, and different ways of performing the exam, asking me to undress, having a gown to put on for the first time, my first prostate check, etc. I'd never been aroused by doctor's appointments like I was then, and fantasized about those memories incessantly, and still do. So, this was much like Natalie's experience as a teen, a greater awareness of Medfet interest coming to me.
In more recent years, as an adult, I've pursued other means of indulging my Medfet interests more frequently than just annual physicals by being a participant in medical studies, and working as a figure model for art classes and groups which often involves being used for anatomical demonstrations.