Where a person's virginity or absence thereof can be confirmed by some sort of sign or symbol immediately visible on them (that is to say, definitely not requiring a gynecological examinationnote ). This can work through magic, Applied Phlebotinum, or simply social convention.
Compare Did You Just Have Sex?, Nerds Are Virgins (nerdiness as a Virginity Flag), Sex Dressed, Virginity Makes You Stupid, Virgin Power, Virgin in a White Dress (clothing as an actual or alleged Virginity Flag), Virgin Vision (the unjustified form of this). Sometimes, this can be faked with a Consummation Counterfeit, as when the MacGuffin is a bloodstain on the sheets.
- Everyone in the world of Loveless has kitty ears and a tail that fall off when they lose their virginity. This connection is conveyed through social cues within the story, and exactly what point defines 'the outer border of virginity' is never really defined. For all the sexually charged atmosphere, the lead is a twelve-year-old boy. A grown woman with ears is teased about still having hers, and having already lost their ears is a sign of some enemy characters' pitiful depravity, but the wider social implications, for example in high school or religious orders, aren't explored, with the most it's addressed being one female high school age character having fake ears that she wears in public.
- Hellsing: Played with. When a vampire fatally drains an opposite-sex human and that human is a virgin, s/he also becomes a vampire. If not, s/he becomes a ghoul. While this makes it easy to tell which opposite-sex victims were virgins or not after the fact, most vampires can't tell which humans are virgins or not before they drink. This leads to some vampires who don't want to sire children (like the starter villain) personally ensuring that their meal is a non-virgin before drinking. Millennium-made vampires are different in that drained victims can only become vampires whether the victim was virgin or not (something Hellsing learned from victims who were far too young to have sex lives).
- Fairy Tail: Larcade's Brown Note ability has no effect on virgins.
- The song in Pod People has an audio technician wearing a shirt that reads "I'm a Virgin".
- Parodied in the MST3K bit from the same episode, where TV's Frank wears a similar shirt.
- In Teeth, Dawn wears handmade t-shirt proclaiming abstinence and a purity ring.
- In The 40-Year-Old Virgin, this is first subverted and then played straight. At first, nobody realizes that the main character is a virgin. On the other hand, the daughter of his primary love interest can tell he's a virgin, somehow having gained the ability to spot anyone's virginity flag simply by virtue of spending her high school days with sexed-up teenage boys.
- In the SF shared world of Medea, the resident alien females lose a pair of legs after having sex.
- In Madeleine L'Engle's Many Waters, only "innocents" can ride unicorns. (Otherwise, they disappear.)
- In Nineteen Eighty-Four, a scarlet sash is the emblem of the Junior Anti-Sex League, which advocates celibacy.
- Invoked by one of the protagonists, who while wearing it has slept with plenty of men, and simply wears it to act like the good patriotic Party member
- In Mercedes Lackey's Tales of the Five Hundred Kingdoms, unicorns act as living 'virgin detectors.' Beautiful, beautiful, brainless virgin detectors... This can cause some issues when one does not want their virginity (or gender for that matter) known.
- In The Bible, after King David's daughter Tamar is raped by her half-brother Amnon, the poor girl tears her garment that was reserved for the King's virgin daughters. Her full brother Absolom immediately realizes what happened when he sees her, and it does NOT end well for Amnon.
- The thranx of the Humanx Commonwealth look a lot like giant praying mantids. Unlike praying mantids, male thranx only lose their vestigial wings the first time they have sex.
- Song at Dawn It is customary for a bride to wear her hair up after consummating her marriage (i.e. losing her virginity.) Estela doesn't do it after her marriage because John isn't interested in doing it with her. Instead, she does it after a traumatic experience with a stable hand that she doesn't want to admit to herself was a mistake.
- In The Black Company short story "Tides Elba", the city's religion the company is stationed in includes that women permanently shave off all the hair below their neckline after losing their virginity. The Black Company being a mercenary outfit full of men with too much time on their hands, this gets discussed at length.
- In The Red Tent, it's mentioned that among the Canaanite wives that Jacob's sons took, the morning after the wedding night, the mother of the bride would run into the tent and steal the bloodstained blanket note , to save just in case Jacob wanted "proof" that the bride was a virgin (and therefore that he had paid a fair price for her). The women of Padan-Aram think this is Squick, and their Ritual of Opening is designed to make it so that there won't be a bloodstain so no one will know whether they're virgins or not and judge their worth by that.
- Used literally in the Kushiel's Legacy books - the first man to have sex with Phedre says he intends to use the white silk cloth she bled on to make a new coat of arms.
- In the fourth series of Misfits, there's a minor character who has the power to make the number of sexual partners a person has had appear on that person's forehead. How the power defines sex for this purpose is not fully specified — but judging from the effect on characters with known sexual histories, receiving oral sex apparently doesn't count.
- Adam Ruins Everything averts this, with Emily explaining in one episode that female physical virginity is effectively non-existent, as the hymen can be torn any number of ways, and it is not uncommon for it to heal.
- Buffy the Vampire Slayer: in "Teacher's Pet", the mantis demon prefers to mate with virginal human males (and bite their heads off, pursuant to mantid custom). Her targets include a jock who, after rescue, threatens to sue if word gets out.
- Starfinder: Ikeshti that fail to mate during their once in a lifetime rutting season transform into large, muscular, and mindless "riveners" that other Ikeshti consider kill-on-sight.
- In Me and My Dick, the virginal Sally's Miss Cooter wears a flower prominently.
- Shepherds in some parts of the world traditionally hang burlap bags of colored dust from the necks of their rams during sheep mating season. This makes it obvious which ewes have copulated and which have not, thanks to the dust-marks the bags leave behind on backs and shoulders.