Children’s movies are made, in part, for grownups—their allegories are meant to pacify both parent and child—but the teen movie, like its audience, is more intemperate. Alternately generous and cruel, it teaches its viewers that life isn’t fair, but that, in spite of pain, they should continue to believe in it. In other words, its job is to break hearts. In the summer of 2014, I sat behind two girls at a matinee of “The Fault in Our Stars,” adapted from John Green’s young-adult novel; the loudness of their weeping, as Shailene Woodley and Ansel Elgort, playing the fatefully linked Hazel and Augustus, were both slowly debilitated by cancer, moved me far more than the histrionics onscreen. There was a similar energy at a recent viewing of “Love, Simon,” Greg Berlanti’s new adaptation of Becky Albertalli’s 2015 novel, “Simon vs. the Homo Sapiens Agenda.” On the way in, a teen-ager with lime-green hair careened into me. “I just have to get a good seat,” she said, sweet and shrill.

The film opens on Simon (Nick Robinson), waking among his bedroom juvenilia in a spruce Georgia suburb. He peers out of his window, yearning for the boy cutting the neighbor’s lawn. “Simon!” a voice pined from the back of the theatre. The audience knew the contours of the character; in Albertalli’s novel, Simon is a closeted high-school junior, a jumpy intellectual, sarcastic and melancholy. He makes a playlist of Elliott Smith and the Smiths called “The Great Depression”; he also peppers his speech with “freaking” and “awesome.” He’s a bit of a goober, on the page—an adorable one, deep in heartsickness. In the book, he’s five feet seven; Robinson, playing an alpha brooder who clenches his jaw and squints like a baby-faced DiCaprio, towers over his provokers.

Berlanti has tweaked Albertalli’s novel in more meaningful ways, too, turning the delirious coming-of-age tale into something more domestic. The novel’s drama derives from Simon’s secret Gmail correspondence with an anonymous student at his school, also closeted, and every other chapter is an assemblage of their letters. The reader takes pleasure in identifying the traits of the escalating communication: the time stamps between messages shorten; the confessions in the body of each e-mail lengthen. The boys start to fantasize about sex, what it would feel like. Berlanti’s film excises much of this; Simon narrates just a few letters in voice-over, and spends most of his time dodging his classmate Martin, a squirrely antagonist who threatens to out Simon unless he sets him up with the plucky and gorgeous Abby. Eventually, Simon gets his boy and there is a big, smacking kiss at the end. But Berlanti’s balancing act for the mainstream leaves little room for the physical expression of gay love. Even compared with, say, “Moonlight,” or “Call Me By Your Name,” this film is chaste; it avoids the oddball raunchiness of mid-aughts efforts like “She’s The Man” and “Mean Girls.” The real romance is between Simon and his own true public identity; his coming out is far more important than his desire.

Berlanti, who was himself closeted in high school, has been a guardian of teen dramas since the nineties. As the showrunner of “Dawson’s Creek,” he orchestrated the smooch between the football star Jack McPhee and his handsome prom date in Season 3. (“There hadn’t been a gay kiss that was romantic on primetime TV,” he reminisced to Vanity Fair, earlier this year.) Berlanti has since sired a bundle of superhero romps that air on the CW, but “Riverdale,” an “Archie” comic rewrite, is the scene stealer. Attitudes about prime-time sex in general have considerably loosened since “Dawson’s Creek,” and “Riverdale,” a murder mystery in which the gay son of the town sheriff cruises at night, is very horny.

“Love, Simon” keeps its protagonist more firmly in check, hewing safely to the heterosexual values of teen romantic comedies, all the while earning Fox its promotional crown of backing “the first mainstream gay teen movie.” In a review, Richard Lawson made the bittersweet observation that there had been no such guide when he was younger, but noted that he wished that Robinson’s Simon “read, frankly, a bit gayer.” (Keiynan Lonsdale, who plays his beau, Blue, came out as bisexual to his followers on Instagram after the film’s completion.) In Albertalli’s book, two of Simon’s friends, Abby and Nick, take him to a gay bar, where he experiences a sense of sublime recognition. The film omits the scene, and instead includes a jokey replacement: a dream sequence in which Simon, a student at “Liberal University,” lacquers his dorm wall with posters of Whitney Houston and dances in rainbow on the quad. He then snaps out of it, shakes his head. This isn’t him; he’s not a stereotype. “I’m just like you,” Simon says, breaking the fourth wall. In such interior monologues, Simon is constantly assuaging the young audience’s anxiety about gayness manifesting in clichéd difference; he is, instead, the poster child of what is sometimes called “homonormativity.”

The film, which leans on the de-facto distinction of its leading man—his gayness—forgets to give him quirks. Simon and his friends are an affluent, telegenic crew, who drink drive-through iced coffees before pulling into the parking lot at Creekwood High. The script is limber and funny, swapping in the contemporary references from the 2015 book with newer quips; one kid, clad in a relaxed button-down and a kitschy lei, goes to a Halloween party dressed like “post-retirement Obama.” Simon gets in a dig at his perfect parents, played by Jennifer Garner and Josh Duhamel, about how their generation loved Bill Cosby. Garner is the “cool mom,” defined not, as is usually the case, by a character flaw (alcoholism, anxiety) but by her political bona fides; she makes protest signs about taking down the patriarchy. It’s clear that Simon’s parents would never have a problem with his sexuality, and neither would his friends—that the struggle, for him, is mostly internal. Berlanti delights in his idea of Gen Z, affirming the studies that forecast that these Americans will reject the “whitelash” and be more queer, more tolerant, than those before them. The two homophobic jocks at Creekwood are repulsive brutes whom no one likes; one of Simon’s classmates, Ethan, who reads as flamboyant, regularly outwits them.

But surely teen-age viewers, who otherwise lose themselves in queer fan-fictions on Tumblr, who march on the street for their rights, could have handled a bolder artwork, one that captured something of gay love rather than making a statement about the straight acceptance of it? The film is as sweet as bubble-gum-flavored medicine; it arrives as if without cinematic lineage—unburdened by cinema’s history of equating gayness with death. It just stops short of producing a picture of gay attraction. I am a mark, but the climactic reunion in the novel—in which Simon sends Blue one last e-mail, inviting him to meet for a ride on the Ferris wheel at a local carnival—made me weep. (“Our pinkie fingers are maybe an inch apart, and it’s as if an invisible current runs through them.”) In the film, the boys’ conversation is intercut with shots of the crowd, roaring from the ground. The moment is tepid—their kiss a win for representation rather than the climax of a consuming crush. A few minutes later, Simon picks up his new boyfriend on his way to school, and Berlanti has them kiss a second time. The coda made the theatre roar. And it was their cheering, not the kiss, that made me emotional.