Al C. asked me: " Question for you -- did your experience have any similar, long-term reactions? I'm older now but until fairly recently I could get an erection by just encountering an attractive nurse or female doctor."
I masturbated for years to the memory of that particular exam. The next time she saw me, two years later, my balls were tight against my body and my cock was maybe a little, tiny bit erect. She was more exasperated (about my balls - she had to kind of pull them down) than anything: "I'd think you'd be more relaxed, since I've seen you before." And the exam in-between, with another female doctor at age 16, she had me hold a towel in front of myself (D'oh!! Female doctors: never do this!!), so she didn't see that I was semi-erect.
I would love, love, love to have another stiff erection at a female-doctor exam, but I'm more calm now. Once went in at about age 30 with testicular pain, and the doctor, a very, very attractive blonde not much older than me, stared at my cock (from very close range) and touched my balls for quite awhile. And I didn't get erect! I was disappointed. But at the same time, I didn't want to appear to be a jerk, so I was glad in that sense not to "pop".
I'm in my 40s now and still sometimes masturbate to nude-exam-erection scenarios, e.g. where they inadvertently put a girl my (teenage) age in the exam room with me, both of us in our underwear and waiting a really long time for the doc, etc. And ultimately she watches as the doctor (female) has me pull down my underwear, etc. ... think I need to go masturbate now, in fact!