As a pudgy 8-year-old in 1974, Bella Grandelli loved few things more than her purple Schwinn with its sparkly green banana seat. At 16, she puffed on pot and prized her driver’s permit. By 29, she worshipped the Wonderbra.

Bella’s evolving material and social must-haves drive Wish, a new book by National Geographic Kids Editor in Chief Melina Gerosa Bellows. Though written for adults who will recognize such “time capsules,” the book is somewhat reminiscent of Francine Pascal’s Sweet Valley series about twin sisters coming of age. Bellows’ Bella even has a twin.

Having grown up in the same time period as the Grandelli twins, the author riddled her book with pop-culture references to the ’70s and ’80s such as Lynyrd Skynyrd and Tab soda. “I definitely had a crush on Cher, and it was a big deal to stay up late to watch The Sonny and Cher Show—and when they got divorced I was very upset about it,” Bellows says. “All that pop-culture stuff [in the book] I hope will resonate with those women who…grew up in that time.”

But Wish is more than a chronology of typical middle-class growing pains and thrills. Bella’s twin brother, Bobby Grandelli, has a type of autism called Asperger’s syndrome, and his condition adds complexity to the plot and characters. Bellows focused on Asperger’s specifically, she says, because it’s a condition with ritualistic behaviors.

“People with Asperger’s syndrome suffer from information overload: Sounds and tastes are completely exaggerated,” explains Bellows, 40, a Capitol Hill resident. If Bobby is touched, for instance, he throws a tantrum. When he’s very happy, he rapidly quotes Yosemite Sam. “It was really fun to write what Bella’s doing and then remember the rules of Asperger’s to figure out what Bobby will do in response.”

Many of Bella’s actions, on the other hand, were inspired by Bellows’ own life. Bella and her creator both went to Catholic colleges: the former to Notre Dame, the latter to Boston College. Both women have had their share of boyfriends (Bellows thanks hers in Wish’s preface). And both were entertainment journalists in the ’90s.

Before arriving at National Geographic Kids, Bellows worked for Premiere, Entertainment Weekly, and Ladies’ Home Journal. The juicy sections detailing Bella’s experiences with celebrity culture—including a pep talk with Oprah—came “right out of my true life history,” Bellows says.

Despite Bellows’ similarity to Bella, and despite the universality of her heroine’s coming of age, the author is perhaps most pleased with the twins’ relationship with each other: The brother and sister are able to communicate their deep affection without conventional speech and touch. Throughout the book—and when, near the end, catastrophe strikes—Bella learns from her brother.

“[In the end], when Bella just doesn’t think Bobby’s going to live, she finally makes peace with [her brother’s fate]. It’s only then that the sweetest reward comes to her,” says Bellows. —Hope Cristol