(that was bad, I know)
Choosing a genre is tough. I have been told and read many things regarding this necessary evil. The most prominent is "In what section of a bookstore would you shelf it?" Well, I'd want mine on the Best Seller shelf! Or at least the Recommended shelf! Ha ha!
Here are some problems I see concerning genre.
What you write matters. Some genres are avoided; some are new, unfamiliar, or made up; and some are trendy. Like Chick Lit was a fad that isn't as popular as it was several years ago. Now YA, Urban Fantasy seem to be hot right now, but I heard Dystopian is taking over, maybe? I wouldn't suggest choosing a genre because it's sought after, but reading agent interviews tells me the majority want those popular ones!
Agents can be fickle. As I research agents, I find a list of what they're seeking. But we need to check multiple sources to see what they really want, because they don't always keep all their sources up to date.
Where does my book fit? My book is a sci fi thriller. But it isn't "hard" or traditional sci fi, it's techno sci fi set in the near future with most things the same, but a bunch of new technology...and there isn't a section for that in the bookstore! So I get lumped into Sci Fi with the other worlds and robots and stuff. Stuff I like, but I feel that people who don't normally look in that section because of the stereotype might like my book. And agents might react the same way, Sci Fi? I don't do that - slush!
Here are some articles on genre that I dug up from names you might recognize:
Jessica @ Bookends, LLC - a Literary Agency
Jodie Renner of Jodie Renner Editing
Janice Hardy from the Other Side of the Story
(these guys have lots of advice for writers!)
In the end, it all comes down to writing a great book and clicking with an agent (or just pubbing it yourself!) What do you think?