The disagreement between the two characters can be explained through their different definitons of ethnicity. Ronnie is Asian American by birth and biological heritage, while Benjamin is described as "blond, blue-eyed, a Midwestern tourist in the big city" (285). As Benjamin tells Ronnie that he too is an Asian American because he was adopted by an Asian American family and that he knows how Ronnie feels being part of a minority, Ronnie counters: "Even though you're blond and blue-eyed" (290). When Benjamin protests that his race is not purely made up of genetic heritage, Ronnie, replies: "If genes don't determine race, what does?" and "You can't just wake up and say 'Gee, I feel black today'" (290). To quote Werner Sollors famous distinction between "descent" and "consent" in determing American ethnicity, Ronnie subscribes to a vision of ethnicity based on descent, while Benjamin has consented to be an Asian American through culture.
Page numbers refer to D. H. Hwang, Trying to Find Chinatown - Selected Plays. Theatre Communications Group, 1999.