I'm generally regarded as a writer of literary fiction – but I have also chosen to write two novels which are set in the past, so I have a foot in the historical camp as well. This difficulty in deciding where I stand as an individual convinced me that the whole idea of "genre" is simply unhelpful. There is a huge overlap between literary and genre fiction – to the point where the labels become meaningless.

To take a personal example: when I had written my novel Girl in a Blue Dress, I didn't initially think about sending it to our local Birmingham publisher. I didn't think it would fit in with the kind of cutting-edge contemporary fiction Tindal Street Press was generally accepting at the time.

My novel was set in the 19th century and not really their cup of tea (I thought). But they made it clear that their only criterion was: is it good writing? That consideration transcended any narrow view about genre. Without that encouragement, I might never have been published, and my writing career might never have taken off. A valuable lesson.

The strange fact is that I didn't – and still don't – think of myself as writing "historical fiction" at all. It's other people who sometimes put me in that category. And I have to admit that I am not altogether comfortable with it. Alongside a lot of people with pretensions to literary writing, I have nursed a prejudice about historical fiction. As a teenage reader, I'd seen the covers of some historical novels and stuck my snobbish little nose right in the air. But at the same time I couldn't get enough of A Tale of Two Cities. So what was going on?

I think I was unthinkingly avoiding what I thought would be cheap writing. And a lot of historical novels (like a lot of mainstream novels) have been badly-written and clunky. But there are many clever and wonderful writers who use settings in the past, like Sarah Waters and Madeleine Miller.

And an author like Hilary Mantel demonstrates how literary style can live alongside a historical story to produce a masterpiece. All of which goes to show that there is nothing in a contemporary setting that automatically gives a novel "literary" status and that novels set in the past are not all ripping yarns or lurid romances.

In fact, writers have always written about the past. Richard III is not a lesser play than, say, Love's Labours Lost because it is not contemporary to Shakespeare's time. And Dickens's novels (even discounting Barnaby Rudge and A Tale of Two Cities) are all setn in a period at least 30 years earlier than when he was actually writing them. Pickwick is actually a Regency figure in his tights and waistcoat, and there are far more stage-coaches than trains in all Dickens's novels, even though they had virtually disappeared from his life. Yet we don't think of Dickens is an "historical novelist" as a result. Which raises the question of how we define the literary past. Most writing is in some sort of past tense, so where does history start? Yesterday? Last year? Last century? Before the war? Is the first world war more "historical" than the second? Or do we say that history is "outside living memory"? If so, the parameters will be different for everybody. I may remember the 80s – but if you don't, is The Bonfire of the Vanities a historical work to you?

For people in a hurry who who don't want to try something different, I feel it's a bit like boys' toys and girls' toys (a categorisation which I dislike intensely). It's the same with women's fiction or black fiction or cult fiction or gay & lesbian fiction. It lessens the content, demeans the reader, puts writers in unnecessary pigeonholes.

My worst review on Amazon was by a bloke who said my first book was written "about a lady, by a lady, for ladies." I didn't mind so much that he didn't like it; that's his prerogative. But to draw the conclusion that the author's gender and the protagonist's gender would make it only suitable for readers of the same gender really grated. It's like saying a war book is only suitable when written by a man, about men, for men to read. Yet a book like Birdsong has been fantastically popular with all kinds of readers.

Genre goes along with our wish to read what we already know that appeals to us. But that's the danger. We could spend all our lives reading within the narrow confines of the genre we know (and think we love) and never set a readerly foot outside it. Genre encourages us to have the same reading experience each time. There's the (probably apocryphal) story that Queen Victoria, after reading Alice in Wonderland, asked Lewis Carroll to send her his next book, and he duly provided a treatise on mathematics. One assumes she was not amused, but similar accidental discoveries could maybe surprise and delight us.

The word "genre" can create an image in the mind that vitiates against genuinely wide reading. For example, I would say I'm not a big fan of science fiction because I tend to find hybrid monsters and oddly-named people in pseudo-mythological settings rather risible. But I need to be given the push to read outside my comfort zone and find wonderful books like Bill the Galactic Hero, Oryx and Crake, and of course The Hitchhikers' Guide to the Galaxy.

You might say Hitchhikers' Guide isn't really science fiction; it's comedy. Or satire. Or drama. But that proves my point. Trying to pigeon-hole a book tends to diminish it, and diminish the chances of a reader actually picking it up. I don't want to think of a book as "good of its type" – just good in itself. I'm more concerned with whether it is well-written, that it fires the imagination, and that it makes me think. The fact that a writer has chosen to set a piece of writing in a previous century or in parallel universe, or in a criminal underworld, or with a war theme, has no relevance at all to its quality. And I therefore contend that there is no essential difference between these "genres" and the other "genre" that is literary fiction.

Gaynor Arnold's The Girl in the Blue Dress was longlisted for the Man Booker and the Orange prize. Her second novel, After Such Kindness, was published in 2012. This is an edited version of a speech given at an Oxford Literary festival debate in support of the motion "Genre fiction is no different from literary fiction".