A musical about seven autistic young adults, played by seven autistic young actors, breaks new ground on Broadway.It would have been enough of a first for a Broadway musical to tell a respectful or even vaguely authentic story about autistic people. On the rare occasions we have seen such characters represented in commercial productions, they have mostly been objects of pity, mockery or fear.So it is a welcome change that the seven autistic characters in “How to Dance in Ohio” are presented, without condescension, as young adults a lot like most others, albeit with unusual gifts and challenges. That they are also played by autistic performers makes the feel-good show, which opened on Sunday at the Belasco Theater, more than a first: It’s a milestone.With all that groundbreaking, perhaps it is no surprise that the production is otherwise very conventional, sometimes dispiritingly so. Just as the characters struggle to conform to the expectations of a neurotypical world, you feel the musical doing a similar thing, looking to traditional models (like “The Prom”) instead of offbeat ones (like “Kimberly Akimbo”) that would be a better fit. And though the result is sometimes uplifting, the uplift comes at the expense of the depth and complexity the show might have achieved were it not so intent on cheerful persuasion.Certainly in its brightness it is nothing like its source material, a 2015 documentary also called “How to Dance in Ohio.” Set at Amigo Family Counseling, a real Columbus mental health center for autistic people, the film, by Alexandra Shiva, highlights the experiences of several clients preparing for a spring formal. Over about 16 weeks, they practice specific applications of the life skills Dr. Emilio Amigo and his staff have been teaching them more generally, whether those skills are social (how to ask for a date), emotional (how to deal with rejection) or physical (how to do the Wobble).The documentary’s tone is objective and thus often dour. Not all its stories are happy: We see some clients struggle to speak, let alone dance. Even for the others, the excitement of the event is countered by fear — both theirs and their parents’, whose faces have been worn by years of worry. By not making the obstacles seem easily surmountable, the movie respects everyone’s hard work, regardless of success.The musical, directed by Sammi Cannold, features a cast of young actors who are all making their Broadway debuts.Sara Krulwich/The New York TimesTo replicate that approach, however truthful, would be a big downer — and, for a commercial show, a fool’s errand. So the musical, directed by Sammi Cannold, instead starts from an assumption of ability and excellence. The young actors, all making their Broadway debuts, are highly skilled, sparkly cute and perfectly comfortable holding the stage.That makes their characters seem perfectly comfortable too. When best friends Caroline (Amelia Fei) and Jessica (Ashley Wool) go to Macy’s with their mothers to buy twirly gowns, you feel that they don’t need, as in the movie, constant assistance and reassurance — just a credit card. And though Tommy, a superhero fan preparing for his driving test, tells us he has “trouble making facial expressions,” the evidence of Conor Tague’s performance says otherwise. His facial expressions, like those of any good actor, would be legible from the back of the Belasco.Lacking the movie’s fundamental contrast of hopes and abilities, the show, by Rebekah Greer Melocik (book and lyrics) and Jacob Yandura (music), focuses on flimsier conflicts. Jessica doesn’t like Caroline’s (unseen) boyfriend, who’s too possessive. Remy (Desmond Luis Edwards) gets some hostile comments on his YouTube cosplay channel. Drew (Liam Pearce) is concerned about attending the prominent university that accepts him. (He’s an engineering savant.) Mel (Imani Russell) has trouble handling criticism once promoted to Head of Reptiles at the local Paws and Claws.Only Marideth (Madison Kopec) retains some of the complexity of the real character she’s based on, at least as seen in the film. When upset by social situations she cannot handle, she may freeze in fear or race out of the room, often into the comfort of the alternative universes she visits on her computer or the real-world facts she collects compulsively. (“You have more bones in your feet than in the rest of your body combined.”) This outlook is beautifully established in “Unlikely Animals,” a number that, like many of the show’s songs, has a thoughtful and poetic (and on-the-nose) hook. “Australia is a lesson,” she sings, “in what isolation and distance can do.”Even so, “How to Dance in Ohio” does not permit much doubt that Marideth and the others will have fun at the formal and achieve at least moderate independence beyond it. To take up the slack, the authors have displaced the story’s crisis onto Dr. Amigo (Caesar Samayoa) himself. An anodyne and often peripheral figure in the movie, he here makes a series of peremptory and bizarre missteps that, in the doldrums of the second act, alienate him from his clients, their parents and, for good measure, his own daughter, Ashley (Cristina Sastre), who works at the clinic and likewise blunders in her dealings with Mel. We are meant to understand that it’s not the autistic characters who need to change but the neurotypical ones.Foreground from left: Wool as Jessica, Desmond Luis Edwards as Remy and Caesar Samayoa as Dr. Emilio Amigo (Caesar Samayoa), who runs a mental health center for autistic people.Sara Krulwich/The New York TimesFair enough, but that story, warmly acted if clumsily executed in a series of impossible hairpin turns, isn’t as distinctive or compelling as the one the movie tells.This being a musical, the compensation is meant to be in the songs, and there is much about Yandura’s music and Melocik’s lyrics to admire. The opening, “Today Is,” in which we meet the clients as they build their lives from bits of memorized routines, is cleverly set to scale-like phrases reminiscent of piano exercises. The expected number at Macy’s turns out to be not for Caroline and Jessica but for their mothers, with the touching refrain “I want to see a picture of my daughter getting ready for the dance.” Throughout, the phrase “how to,” sung by almost everyone as they stumble their way forward — “how to set clear boundaries,” “how to manage long-term grief” — suggests that people have more in common than their different kinds of wiring might suggest.But stepping too hard on the dramatic accelerator, the book strips its gears as it goes along, often resorting to advocacy jargon (“nothing about us without us”) and flat-out cheerleading. Nor can the minimal production do much to deliver the oomph it clearly wants as the story reaches for a Broadway ending.Perhaps it’s enough that “How to Dance in Ohio” offers solace and encouragement in a mild, conventional package. (There are cool-down spaces for those who need them, as one of the actors explains in welcoming the audience.) Doing sweet, reparative work for any part of humanity means doing sweet, reparative work for it all.How to Dance in OhioAt the Belasco Theater, Manhattan; howtodanceinohiomusical.com. Running time: 2 hours 25 minutes. More