The doctor asked her if she could be pregnant, and my daughter told her that she is a virgin.
I suspect that somewhere in hospital history, there is at least one case of a teenager denying sexual activity on their history, especially if asked in front of a parent. And while I believe your daughter was telling the truth, if the treatment that they were contemplating in any way was contraindicated with pregnancy and they administered it anyway and she was pregnant, I can see lawsuits everywhere. Stomach pain in a healthy teenage girl can be a symptom of miscarriage and/or eptopic pregnancy, the latter of which can be very serious.
Both my daughters went on birth control pills during their freshman years of college - the combination of odd sleeping schedules and living with so many girls threw their periods off as well as made them much more heavy and more frequent. Each saw a different practitioner for their exams, and the rule of thumb seemed to be if they aren't sexually active, then they don't do a pap smear until 21, or whenever they become sexually active, whichever comes first. Otherwise, both could have waited until age 21 for their first exam. While no young lady enjoys this invasion of privacy, it is imperative that we, as their mothers, set a positive tone for doing things we don't like, in order to screen for certain diseases and disorders. The best way to send this message is to drop hints to your daughters when you go for your yearly exams (or whatever schedule you're on), and especially when you go for your mammograms.