It would be difficult to try to categorize Nancy Werlin's National Book Award Finalist YA novel Impossible. It doesn't feel quite dark enough to be urban fantasy, not enough fantasy elements for standard YA fantasy, but not realistic enough to be realistic fiction. The romance is wonderful but not graphic or overdone. What it am going to call it is just a really good book. It is based on the song "Scarborough Fair" made famous by Simon and Garfunkle.
Lucy Scarborough is one of the women in a long line of women who have been cursed by the Elf Knight - they will go insane at the birth of their first child (always a daughter) unless they can complete three seemingly impossible tasks. Lucy is lucky enough to have fantastic foster parents (since her mom is crazy) and Zach who are willing to try to break the curse.