When I started this thread I wasn't really concentrated on virginity, per se, but Spoogesicle's post (#10) makes a distinction that I had not considered and clarifies for me how I inadvertently confused the issues. The distinction between "having sex" and "having intercourse" is, indeed, huge. Of those two, I actually am interested in the first: What counts as having sex? Virginity, as it turns out, is not the definitive marker that I thought it was.
By way of apology to Gisella: I am not among those who elevate virginity. I was not a virgin by anyone's definition at my marriage, and neither was my wife with whom I had already been living for some time before we wed. I did not mean to endorse by fraternity brother's obsession with technical virginity, in fact my sympathies at the time (now almost 30 years ago) were with his first girlfriend, who was a kind and thoughtful person. He was a real prig.
I thought it was a useful example because it actually contained four distinct perspectives about sex:
1. My best friend's, who was sure he had had sex via anal intercourse but did not think that applied to the woman he had sex with.
2. My priggish frat brother's, who felt that all forms of sex short of vaginal intercourse were not sex.
3. The dumped girlfriend who believed that she was not a virgin having had intercourse once, but thought her boyfriend was, despite his sexual activity outside intercourse.
4. The "Devirginator" who did not hold that she had had sex ever, though literally dozens of men thought they had had sex with her.
I can see, however, how anyone could have misunderstood the reason for my example, because I failed to make Spoogesicle's simple distinction. I thought of virginity as the definitive marker of “having had sex,” which turns out not to be the case. Everything might have been clearer had I not included that example at all.
As Lord Pendragon points out, my starting point was another thread on which, as a game, we tried to guess the number of sexual partners other posters have had. It quickly became apparent that those were calculated in vastly different ways. (Because most of my sexual partners have been men, my own largish response would be reduced to a single digit if I used Pendragon's definition, for example.) It made me wonder what constitutes "having sex.” This thread has already shown that there are almost as many definitions as posters.