The concept #OwnVoices (coined by writer Corinne Duyvis) describes a book in which the author and the character(s) share a marginalized identity [for example a queer Black author writing a queer Black character]. #OwnVoices is a call to action to publishers and librarians to uplift not only "diverse" stories, but diverse stories by diverse authors. This is especially important as the publishing industry continues to be predominantly white, cisgender, straight, and female [1, 2, 3].
[1] Just How White Is the Book Industry?
[2] Where Is the Diversity in Publishing? The 2019 Diversity Baseline Survey Results
[3] Penguin Random House U.S. Publishing Programs Audit Findings
Considerations...
Many authors of marginalized identities will highlight their identities on the "about" or "bio" pages of their websites. If the author has a Wikipedia page, Wikipedia has categories at bottom of their pages that may assist in discerning identities (ex. Chimamanda Ngozi Adichie, American writers of African descent; Roxane Gay, LGBT African Americans).