As Leo goes on a journey to connect with his biological father, he comes to understand his own identity in new ways.

Leo connects his identity to his genetics in the very first chapter, when he explains how he has “McMurphy, the eight-hundred-pound gorilla […] in my DNA, a total loose cannon rolling around my personality” (5). McMurphy is later revealed to be the last name of Leo’s biological father, whom Leo has never met. In Chapter 4, Leo recounts first learning about Marion X. McMurphy and feeling like “I wasn’t quite me anymore” (33). Leo felt “Something had gotten into me—or more precisely, someone. I’d try to be good […] And then I’d feel McMurphy rising” (34). Leo separates himself from his internal McMurphy because he is not connected to the McMurphy side of his genes. Rather than accept the parts of his identity that might be unruly, Leo others this behavior as the work of McMurphy, an alter-ego he rejects and refers to as a “genetic hitchhiker” (25) and “a security breach” (34). This feeling of split personality is so pervasive that McMurphy feels like a whole other entity: Leo even narrates, “I knew I wasn’t alone in there” (34), referring to his own mind.