I recently participated in a pitch contest and saw a lot of people pitching their novels as “Adult Sci-Fi” or “Adult Historical Romance.” Now, I was under the impression anything not labeled NA, MG, or YA was automatically considered Adult. Has that changed?
Second, the characters in my fantasy novel fall within the age range of NA. When I started the novel, NA didn’t exist. I can make the case, however, that the themes fit within the NA genre even though I consider it to be aimed at adults. I know it is ill-advised to put multiple age brackets in your genre (pick one, most would say). My plan is to list it as Adult but can I say “with NA crossover potential” without getting my query deleted?
The answer to your first question is No, that has NOT changed. Anything not labeled MG or YA is considered adult (notice I left out NA.)
The reason (I'm guessing here) that people said "Adult historical romance" was because of the forum. In a pitch contest (rather than a query letter) writers are not targeting specific agents so they need to quantify some things that would be obvious if they were querying one agent at a time.
Second, the advent of New Adult is making everyone crazy, not just you. No one really knows what it is for sure and a lot of things get called New Adult that are really just YA with sex. I've seen things that we thought were erotica called "New Adult."
Leave out the "with NA crossover potential" because no one really knows what that is yet.
Your plan should be to list it by category: fiction/crime/sf/f/western; and, time: contemporary/historical. Leave out the other stuff.
Remember, we're looking for good writing across the board. You write a good crime novel with a protagonist who's 17 or 77 and you've got my attention.