Literary genre is used by bookstores to separate books into different sections. It’s also a matter of life and death for many readers/writers to assign a genre or not to the book of another writer.
Margaret Atwood is an example of peer or reader pressure in telling you to which genre your book belongs – “If it is realistic or plausible, then it is not science fiction.” she explained. (http://io9.gizmodo.com/5847421/if-it-is-realistic-or-plausible-then-it-is-not-science-fiction)
Svetlana Alexievich, Nobel Prize for Literature winner in 2015 (https://en.wikipedia.org/wiki/Svetlana_Alexievich) , represents a different attempt to redefine not only literary genre, but to expand the definition of literature previously given by the Nobel Prize committee to nonfiction. “The material that she’s offering us – she’s actually devised a new kind of literary genre – that speaks to her achievement,” said Sara Danius, Permanent Secretary of the Swedish Academy.
How much it really matters on which shelf people place your book?