What is the theme in Confessions of an Ugly Stepsister by Gregory Maguire?

Beauty versus charity is a theme in the book. Iris believes beauty has great value when she is a young girl. Her mother tells her that she can never hope to marry because she is ugly and that that makes her a burden. Margarethe thinks she is cursed with two daughters she must care for because they have no prospects. She uses them as a point of pity. Margarethe complains of the lack of charity the people of Haarlem display. No one is interested in them as beggars and no one wants to hire her as she yells her sad story on the street. Schoonmaker shows her charity, but she repays him by abandoning him as soon as a more profitable offer is presented.