McMurphy is the last name of Leo’s biological father and the name Leo assigns to the part of his identity that comes from the McMurphy genes. Leo’s version of McMurphy serves as a motif for the theme of Genetics and Identity by showing how Leo links his McMurphy genes to aspects of himself.

McMurphy’s first mention is in Chapter 1, when Leo explains that he has “McMurphy, the eight-hundred-pound gorilla I carry in my DNA, a total loose cannon rolling around in my personality” (5). For much of the novel, Leo treats McMurphy like a separate entity from himself, referring to McMurphy as a “genetic hitchhiker” (24) and a “security breach” (34). Leo’s othering of McMurphy from himself began when he was ten and first discovered his biological father is a stranger named Marion X. McMurphy. From that point on, he began “replaying my entire life. Every misstep, broken rule, and temper tantrum—had that been him, hovering just below the radar screen?” (34-35). Leo also states in Chapter 1 that he joined the Young Republicans to “help myself control McMurphy” (5). Leo’s feelings toward McMurphy shows how he others and suppresses parts of himself that he deems unacceptable rather than exploring and accepting the full spectrum of his identity.