On a writing list a person said “I once was in a critique group with a writer who wrote Westerns. Except she’d never read them. Not one.” Let me put my writing hat on for a moment and comment on that.
There are reasons for reading in the genre we are writing in. First, we should be aware of our competition and know how and what they are writing. There will come a time when we need to identify comparables that will help us define our reader base. We’ll need to know why we consider them comparables but also how our books differ.
Second, it is terribly difficult to do a credible job writing in a genre if we are not steeped in that genre. If we are reading literary fiction, for example, but trying to write genre westerns, it is likely to influence our writing in a manner that editors who know what that particular reader base like will not appreciate.
Third, how do we know if our writing is any good if we don’t have anything to measure it against?
Fourth, there are a lot of “conventions” particularly in writing genre fiction. We may can find classes to teach us that, but still one of the best ways is to read in our genre a lot so we know how similar stories are constructed. To know what reader expectations are.
And finally, why on earth would we not be supporting the genre we are trying to write in?