The most compelling part of the dialogue between Ronnie, the ethnic Chinese young man, and Benjamin, the blue-eyed Caucasian from Wisconsin (or "Wuss-consin," as Ronnie describes it) is that neither character ultimately convinces the other that identity is dependent on ethnicity (Ronnie) or on cultural inheritance (Benjamin). In fact, the last lines of the play show us two characters who have missed a chance to understand the complexity of identity. In the last stage direction, we see that these two characters have passed each other like ships in the night:
(Benjamin sucks his salted plum and listens to the sounds around him. Ronnie continues to play. The two remain oblivious of one another. Light fades slowly to black.)
Clearly, Ronnie has failed to understand Benjamin's cultural "Chinese-ness" founded upon the nurturing of his Chinese parents, which Ronnie dismisses out-of-hand because Benjamin simply doesn't look Chinese. At the same time, Benjamin laments Ronnie's failure to appreciate his Chinese heritage--and gives no thought to the possibility that Ronnie identifies himself not by his Chinese ethnicity but by his love of jazz and the violin.
Hwang's stage direction at the end of the play implies that one's cultural and ethnic identity is an amalgam of nature and nurture but, more important, how one identifies oneself may be the result of something other than ethnicity and nurturing--Ronnie seems to be a product of neither.
The issue of whether identity derives from genes or one's nurturing is beside the point in this play. The fact that the characters, at the play's conclusion, are in their own worlds, oblivious of one another, testifies to the complex inability of us all to fully resolve issues of identity, issues that are made much more difficult for an individual who has two cultures, two ethnicities, and another force pulling him or her in three directions--nature, nurture, personal inclination.