Anna stands out as the book’s most conflicted character. Her connection with Kate, and her struggle to exist independently of that connection, both define her. She tells Campbell, for instance, that of all the things she might want to be in ten years, what she most wants to be is Kate’s sister. At the same time, Anna desperately wants to exist independently of Kate, but she knows she cannot do so as long as her main purpose in life consists of keeping Kate alive. These contradictory feelings make up the tragic core of Anna’s character. She feels a tremendous sense of guilt for wanting to live separate from Kate and wonders if she is an awful person for feeling that way. As if trying to roleplay the part of an awful person, she even begins to indulge in self-destructive behaviors, such as smoking, with Jesse. But Anna also wants to do what’s best for her sister. Kate, we learn, ultimately decides that she no longer wants to live, so Anna, although it hurts her deeply, brings a lawsuit against her parents for medical emancipation. The lawsuit satisfies both desires: it gives Anna control of her own body, allowing her to put her own interests before Kate’s; and since Kate will die without Anna’s kidney, Anna can fulfill Kate’s wish to die.
Anna also represents the point where science and humanity intersect. Her parents conceived her—with the aid of scientists—for a very specific reason: to provide Kate with a genetic match whose organs could help keep Kate alive. Sara even admits she could only think of the unborn Anna in terms of what she could do for Kate. Despite this scientific reason for Anna’s existence, she clearly amounts to more than just a donor, both to her family and to the reader. Anna is funny and thoughtful, described by Brian as the family’s constant and source of light. She has contributed to the Fitzgerald family on far more than a medical level. Her emotional attributes have helped Kate just as often as her physical ones. Thus, Anna’s life suggests that no matter how far science advances in its ability to engineer humans for a purpose, those humans are still thinking, feeling people who will always mean more than just their scientific reason for being.
Sara acts first and foremost as a mother throughout the novel, and her need to keep her daughter, Kate, alive motivates her more than any other impulse. Whatever other problem she encounters, be it Jesse’s delinquency or Anna’s need for independence, the matter holds less importance for her than Kate’s survival. Paradoxically, by focusing so much on being a mother to Kate, Sara does not always fill the role of mother for her other children. For instance, Sara tends to disregard Jesse’s self-destructive behavior, which Jesse uses to call out for attention, and she doesn’t stop to think that Anna might be genuinely unhappy when Anna files the lawsuit for medical emancipation. Although Sara undoubtedly loves Jesse and Anna, she has difficulty considering them as people separate from Kate. Similarly, though Sara is a wife to Brian and a sister to Zanne, her relationships with these people also revolve around Kate. Sara struggles to talk to Brian about anything other than Kate, for instance, and the few times she sees her sister occur when Zanne comes to take care of Jesse and Anna because Sara is going with Kate to the hospital. Even with Kate, Sara focuses mostly on her physical, rather than emotional, health. For example, when Anna reveals on the stand that Kate doesn’t want to live any longer, Sara does not believe it because she has never spoken to Kate about these feelings.
Over the course of the novel, Campbell evolves from a sarcastic, emotionally aloof opportunist who fears intimacy into a person who—though still sarcastic—is more trusting, open, and truly cares about the wellbeing of Anna and her family. At the beginning of the story, Campbell has almost no friends, except for his service dog, Judge. Instead, he keeps himself closed off from others, fearing his epilepsy will cause people to pity him or think him a burden, and he uses his sarcasm to hold people at a distance. He repeatedly tells bad jokes about why he needs a service dog, for instance, and he alternates between caring about Anna and using her case for publicity. Once he begins to care about Anna and to reconnect with Julia, however, Campbell begins opening himself up to new relationships. In fact, Campbell’s epilepsy and the resulting lack of control he feels over his own body even help him to bond with Anna, who also feels, albeit in a different way, that she has no control over her body. Eventually Campbell starts being honest about his feelings, and less sarcasm appears in his conversations. By the end of the novel, he agrees to act with power of attorney for Anna’s medical decisions, proving the two have established a bond as the relationship means they would have to stay in touch at least through Anna’s eighteenth birthday. We also learn that Campbell and Julia eventually marry, and that they remained friends with the Fitzgeralds for a time.