[Image: "Well yes, but actually no" meme]Agents have manuscript wish lists and interest lists for a reason: that's their area of expertise. You wouldn't take a motorcycle to a mechanic who only works on trucks. In the same vein, agents explicitly state what genres and age categories they're interested in (and often what they don't want to see) not only because they prefer to read that sort of work, but also because they have connections in that type of literature. That is their field, and as querying writers, it's our job to respect that.
It's not only a bad idea to send a manuscript in a genre an agent doesn't represent, it's unprofessional. It's like saying to the agent that you know they have preferences, but you're choosing to ignore them. Angie Hodapp at the Nelson Literary Agency said it best:
At the end of the day, you shouldn't query an agent who doesn't represent your genre. Period."Dear Agent: I read on your blog that X doesn't work 99.9% of the time, but I believe my novel might be the exception." #doubtit #pubtip— Angie Hodapp (@angiehodapp) June 30, 2015