Sex is weird. If there’s one thing we can take away from the 10 years since Stephenie Meyer’s Twilight was published (happy birthday), with its message of blood lust and bloody abstinence, it’s that sex is weird. There is more. There is the vampire mythology. The swooning, mooning gothic morbidity and how it’s seeped into the culture, creating a generation of sadboys not seen since the Smiths. There’s the question of the enduring appeal of its rescue plot and why the reader (whether 14 or 40) metamorphoses on their sofa into pale little Bella Swan, collapsing into the arms of the most beautiful man in the world. A man that falls in love with you – pathetic, flawed old clumsy you – because the very smell of you, of your blood, intoxicates him. You are the only person in his centuries of trudging through small-town Americas that has made him feel this yearning so yearny he can’t even touch your hand for fear of it overwhelming him and forcing him to eat you. What fun. But thrusting beneath it all is the question of whether Edward really wants to sleep with Bella or instead simply rip her head off. Sex, we learned: it’s weird.

By Eva Wiseman

As the book’s 10th anniversary arrives (with Meyer’s retelling of the story, where the genders have been swapped. She didn’t have time, she told the Guardian, to write a new novel, but was “nettled by longstanding criticisms of Bella for being weak and in need of constant rescuing, as well as ‘too consumed with her love interest’, as if that’s somehow just a girl thing”), we can look back at what we thought Twilight was teaching teenagers about sex and then, what it really taught them.

“For every page of chaste longing there would soon be a thousand pages of explicit fan fiction online.”

Rather than focusing on abstinence, Twilight told readers that chastity is the most erotic choice you can make. Not only is it impossibly romantic, the idea of waiting for marriage before you sleep together, the Twilight version is impossibly sexy. Because abstinence and sex rely on each other. One bashes you round the head with a lingeried brick, dizzying you with suggestions of nighttime and necks, while the other leads you into a candlelit room and shuts the door. And just as diets make you fatter, abstinence makes you, if not pregnant, then leaning that way. Critics gasped at Twilight for telling teenagers to stay virgins, but they needn’t have worried – today there’s no such thing. As Jessica Valenti clarified in her book The Purity Myth, there is no “diagnostic standard for virginity”. Does anybody still believe sex happens only when a man penetrates a woman? Virginity – and the shame, confusion, pain – is an outmoded concept. Not only that but (according to a 23-year-study in human sexuality) women are enjoying their first sexual experience more than ever before.

And what nobody could have guessed when Twilight was first published was that for every page of chaste longing there would soon be a thousand pages of fanfiction online, each describing the consummation of Bella and Edward’s love in such explicit detail that, upon opening them on a laptop, Firefox appears to blush. The most famous was EL James’s Fifty Shades of Grey, another “sex is weird” franchise, but one that managed to wring out any potential eroticism from the story with lines like: “I feel the colour in my cheeks rising again. I must be the colour of the Communist Manifesto.”

Despite its EL James legacy, and Meyer’s Mormon insistence on the sinfulness of premarital sex, we see that Twilight didn’t confuse readers. Rather than pour ice on their adolescent fantasies by focusing them on these undead, unhaveable lovers (rather than the awkward, living options in their English class), Twilight was so popular that the ideas it inspired have surely improved the chances of its fans knowing what they want and how to ask for it.

The decade of Twilight has produced a whole library of lit-crit. But as its readers come of age, 25ish now, all thoughts of vampires staked through the heart replaced by Tinder, the liberal dismay at the book’s assumed message has been forgotten. It didn’t ruin girls; it didn’t leave them unfulfilled. The debates now seem naive. Because how could middle-aged critics hope to understand the dark complexities of adolescent female sexuality? In telling teenage readers a story about the romance of abstinence, Twilight, it turns out, was quietly turning them on.