On this show, guest host Kate Burton introduces two stories that look at the joys and complexity of motherhood. They were chosen by the novelist Celeste Ng and memoirist and essayist Mary Karr. In “Looking for a Thief,” by Danielle Lazarin, a suburban mother questions her choices. The story is performed by Heather Burns. And Burton reads Tillie Olsen’s “I Stand Here Ironing,” in which another mother wonders if she’s done right by a challenging first child.