Mother Knows Best is a wonderful psychological thriller! Kira Peikoff, with her characters, delves into the morality of genetic altering to eliminate the chances of passing on fatal diseases, and the hope of a woman that wants a child that is free from the genetic mutation, she had previously passed to her son. The adults make choices that affect all their lives, and the life of a little girl that now wants answers. A school project is the beginning. I felt the thought process for a 5th grader was a little sophisticated, but it didn't detract from the story much. There are several twists, some predictable, some not. Overall it's a great book, and I highly recommend it to fans of psychological thrillers.