Define your terms, please.

According to Sturgeon’s Law, 90% of anything is crap. It was named after Theodore Sturgeon, who came to the defence of science fiction in the 1950s. “The claim (or fact) that 90% of science fiction is crap is ultimately uninformative, because science fiction conforms to the same trends of quality as all other artforms,” Sturgeon mused, confirming both the truth and the futility of his theory – ultimately, it comes down to how one defines “crap”.

Sturgeon’s law was cited during a provocative debate midway through the Edinburgh international book festival on a question that has dominated discussion for 10 days: how to define young adult (YA) fiction. But despite the intensity and frequency of this conversation, with speakers including Frances Hardinge, Marcus Sedgwick and Simon Mayo, no one – not even the authors writing the books – seems sure how to define it.

Was it born from SE Hinton’s The Outsiders in the 1950s? From Alan Garner in the 60s? Is it, as a teacher was lambasted for writing in the TES last week, all about “a transgender school dropout with autism who meets a self-harming vampire with a heart of gold?” Or, is it a definition in flux, still being determined by contemporary authors as they write their books (which, without an exception, were reported to be “written for themselves”, not teens, a claim that seems at least partly untrue and somehow always defensive against some unspoken attack)?

“The great YA debate” at the festival on that middle Monday embodied the erratic focus of any debate about how to define YA, a topic that regularly bubbles up and always gets sidetracked. Is YA a genre or a category? Who reads it? Is it too grown up? Badly written? Not funny enough?

To bursts of nervous laughter, YA author Anthony McGowan kicked it off by citing Sturgeon’s Law: 90% of YA was crap, pandered to by an audience that treated the whole thing as a “this kind of amorphous quasi religion”, more of a cult than category. He lamented speaking to “monocultural audiences” of white, older women at YA conferences. Some misogynistic, cause-and-effect musing began: most YA bloggers were women, all his editors were women, “so there is a huge amount of energy directing these kinds of texts, texts that may well appeal to women in their 20s and 30s rather than to teenagers. We’ve got this female-dominated world producing texts that reflect themselves, for other young adult women,” he said, perhaps unaware of the significance of making links between gender and perceived quality.

YA may not be a genre (it is a category, as is so often sighed), but the debate devolved into a value judgment regardless, as debates around genre so often do. “I don’t think adults should read YA stuff,” McGowan argued, as authors such as Elizabeth Wein and James Womack disagreed. “I think they should move on and read Tolstoy and Dostoyevsky or Dickens and stop reading Twilight and The Hunger Games,” McGowan said. “It is part of being a grown-up, you leave those things behind...”