There exists in folklore from various cultures of a condition in which rows of teeth are present in the female genitalia. The purpose of these stories, like most folktales, was to serve as a morality tale. This one was particularly geared towards males, and warned against the dangers of promiscuity with "loose" women, or to highlight the consequences of sexual aggression. This was recently brought to life in a comedy in which an individual engaged in sexual encounters with numerous men, and the results were unfortunate.

How could this have developed as a real condition in our species?

  • $\begingroup$ This question reminds me of a US politician claiming that a woman's body would prevent pregnancy from rape $\endgroup$ – nzaman Oct 31 '18 at 15:39
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    $\begingroup$ pathological or normal condition? $\endgroup$ – L.Dutch Oct 31 '18 at 15:44
  • $\begingroup$ @nzaman wasn't trying to imply that. Just a hypothetical about a mythological tale and the movie teeth. $\endgroup$ – Incognito Oct 31 '18 at 15:45
  • $\begingroup$ Incognito: But the obvious implication is @Separatrix' answer. $\endgroup$ – nzaman Oct 31 '18 at 16:02
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    $\begingroup$ @nzaman, yep, the current generation of politicians struggle to distinguish between people and ducks $\endgroup$ – Separatrix Oct 31 '18 at 19:42


In this case Mallards

Yep, those little birds that you see out on the pond going quack are one of the nastiest creatures in the animal kingdom. They're one of the few bird species capable of penetrative sex without consent and they're known for their tendency to commit gang rape.

Since the females don't want to have eggs by any old rapist, they've evolved counter measures.

They discovered that the longer and more elaborate the male member, the longer and more elaborate its female recipient was.

Some vaginas had spiral channels that would impede sex by twisting in the opposite direction to that of the male phallus. Others had as many as eight cul-de-sac pouches en route, that could prevent fertilisation by capturing unwelcome sperm. Moreover, these features were only found in species renowned for forced sex. All other species had simple male and female genitalia.

“These structures are wonderfully devious, sending sperm down the wrong road or impeding penetration,” says Birkhead.

He says that the features demonstrate an evolutionary “arms race” in which control over reproduction alternates between the sexes. If the male develops a longer, more elaborate phallus to force copulation, females wrest back control by developing features to thwart males who rape.

This is a passive or semi-active preventative measure though, you're seeking violent counter measures that would affect the ability of the species as a whole to reproduce. As such you need to create a situation where, should non-consensual sex occur, it has a similar or greater detrimental effect on the reproduction of the species as a whole.

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    $\begingroup$ Excellent answer: As an example of situation where defensive measures could evolve, you can have humanity split into two tribes, eloi and morloks. Either morlok are genetically less fit (e.g. less fertile), or Eloi kill amy woman that gives birth to a half-morlock child. But Morlok men like to impregnate Eloi women, either b/c their own women are even less fertile, or b/c it is a status symbol. As for how to get "teeth", you can have pubic hair evolve into quills or spikes (they are all made from keratin) $\endgroup$ – Bald Bear Oct 31 '18 at 17:30
  • $\begingroup$ Different channels and structures are more of a "soft" barrier, though, which don't present any inherent difficulties for an egg. You would just need more or different muscular action in order to pass it through. How would a "hard" barrier like teeth be able to evolve without presenting immediate and detrimental effects on the birthing process? $\endgroup$ – Alan T. Nov 2 '18 at 13:33

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