I remember a time when writing "he or she" rather than the ubiquitous "he" felt radical. Now I have friends who use the pronoun "they" to refer to themselves, and others who used to be "he" and are now "she" or vice versa. The range of socially embraced gender identities, at least in parts of the world, has vastly expanded.

Fortunately for young readers and their caregivers, books like Theresa Thorn and Noah Grigni's It Feels Good to Be Yourself directly address the burgeoning possibilities and accompanying vocabulary. Illustrator Grigni beckons us in with a spirited, cheerful picture of children on a city street — riding a unicyle, playing a guitar, disembarking from a school bus — as Thorn starts to introduce us to a variety of young people. Ruthie, who's just getting home from school, climbing her steps in a pink dress with her wavy hair swept back in a ponytail, is a transgender girl. Thorn explains: "That means when she was born, everyone thought she was a boy. Until she grew a little older — old enough to tell everyone that she's actually a girl. GIRL is Ruthie's gender identity."

As Ruthie enters her house and gives her mother a big hug, we're introduced to her brother Xavier, who is cisgender — his gender identity as a boy matches his gender at birth. Thorn continues to carry readers through potentially unfamiliar vocabulary and concepts, like non-binary, someone "who doesn't feel exactly like a boy or a girl." She explains that feelings about gender can change over time, even day to day, and that sometimes none of the descriptive words exactly fit. She reassures readers that "Your feelings about your gender are real. ... No matter what your gender identity is, you are okay exactly the way you are. And you are loved." Grigni's illustrations, meanwhile, show nothing but acceptance: hugs, smiles, waves, high-fives, respectful conversations, creative play.

The book's final four pages contain a list of helpful terms to know, a note about pronouns that explains how to be sensitive to what pronouns people use for themselves, and a solid range of resources: more children's books, books for adults, a documentary film, and organizations and helplines.

In her closing note, Thorn explains that her transgender daughter has taught her about withholding judgment. That wholehearted acceptance is an experience Thorn wants for all kids, everywhere.

Grigni came out as trans at age 14 and recognizes that "I'm lucky to have parents who listened and stood up for me when others failed to." Grigni's final paragraph, poignant and powerful, is worth quoting in full:

"We need more books with trans protagonists. The trans population is as diverse as the human population, and no number of books could hold all our stories. Dear reader, it's up to you to continue this work, rewrite these definitions, share your stories, and build a future more expansive than we can imagine. You are the future we're fighting for."