The son of legendary science fiction and fantasy author Ursula K. Le Guin revealed that he updated the language in some of his mother’s children’s books.

In an essay for Literary Hub, Theo Downes-Le Guin, the executor of Le Guin’s literary estate, wrote that he changed the language in three of the late author’s Catwings series of picture books.

The series debuted in 1988 with Catwings, illustrated by S.D. Schindler. The book tells the story of four kittens born with the ability to fly. Three more books in the series followed: Catwings Return, Wonderful Alexander and the Catwings, and Jane on Her Own.

Downes-Le Guin said that the books’ new publisher proposed changing words including “dumb,” “stupid,” “lame,” and “queer.” He noted that his mother had revised her own works previously, and wrote, “After deep breaths, and with Ursula’s own revisionism in mind, I contacted a disability rights attorney, a youth literature consultant, a racial educator, and some kids. My advisory group leaned toward change but was not in consensus. I genuinely didn’t know what my mother would have decided.”

Downes-Le Guin noted the recent controversy over changes in language made to children’s books by Roald Dahl. The books’ U.K. publisher edited some of the books to remove words including “fat” and “ugly.”

“Dahl and my mother could not be more different as writers and as humans, but they had in common a profound trust and affection for their child readers,” Downes-Le Guin wrote. “Consistent with that posture, I would say that kids intuit and accept better than adults that language is constantly in flux, as are human sensibilities.”

Michael Schaub, a journalist and regular contributor to NPR, lives near Austin, Texas.