While the novel does not center on sexual themes, it does explore Charlie's sexual repression, which results from a traumatic childhood. His mother, worried that her "retarded" son might pose a sexual threat to his "normal" sister, harshly suppressed any typical adolescent expressions of sexuality. As Charlie matures, gaining greater intelligence, he initially finds it difficult to establish a sexual relationship with Fay Lillman, a neighbor who enjoys his company. He also faces challenges in developing a physical relationship with Alice Kinnian, the woman he loves. Charlie's eventual ability to have intimate relationships with Fay and later Alice is depicted as a crucial step in overcoming his past traumas and becoming a fully functioning adult.