Here is a funny and possibly useful post from Janet Reid, who as you no doubt know is the agent who runs Query Shark (in addition to her regular blog where she posts about agenting and stuff).
What you say / What I hear, about how agents (Or she, at least) responds to certain typical lines in a query.
What you say: This novel has elements of sci-fi/thriller/YA/romance
What I hear: “My novel will appeal to EVERYBODY!”
What I do: skim the first page to verify you don’t know what you’re writing.
Your take away from this: Your book will not appeal to everyone. Get over it. Pick one category.
I think I especially like that one because it could be a real trap for me. I also would have trouble avoiding this. I’d me all like, Well, it DOES have elements of SF and triller and romance and western and horror, and I don’t KNOW whether to call it a YA or not…
So I sympathize with those who put that kind of thing in their query. But, don’t.
Janet offers half a dozen more examples of things not to put in queries, too.
Incidentally, sometimes the main female lead really can be a prostitute without the story falling into the category Janet describes in 4th example. I loved “Pretty Woman.” I grant you, the exact sentence Janet uses as her bad example does imply a different kind of story. After all, in “Pretty Woman,” the protagonist *was* the woman, not the guy she beguiled.