Wai Tung's parents seem to hold divergent expectations and priorities for their son; in the end, the mother is more upset about Wei Tung's homosexuality than is the father because for him, the bottom line is the birth of the grandchild, and consequently the continuation of the Gao lineage, rather than a heterosexual marriage per se. However, Wei Tung's mother sees his homosexuality as a failure on her part and hopes that he will turn straight after seeing his baby for the first time, indicating her prioritization of customary social roles and acceptance into mainstream society (Taiwanese or American). In fact, while tending to the plants in the backyard before her departure, she metaphorically says: "This garden will grow wild after I leave."
On the surface, Ang Lee makes it obvious that Simon would be the perfect Taiwanese wife if not for his gender and sexuality. He cooks, speaks Mandarin (albeit choppy Mandarin), and as a physical therapist, is even able to help Wei Tung's father after his mild stroke. However, Simon "Asian-ness" is comprised of no more than token gestures, his suggestion of ordering sushi seems to indicate the exchangability of Asian cultures and that he is still just a contemporary white consumer within the transnational economy. In contrast, Wei Wei demonstrates a more politically sensitive (or insensitive?) knowledge of history, stating defiantly "the sixth floor has been liberated" when Wei Tung comes to collect the rent and "I'm liberating you" during their sexual union.
Finally, I am not sure how to interpret the very last of image of Wei Tung's father being checked by the security guard before boarding his flight. The routine screening in this instance done on a foreigner may contain connotations of disempowerment and foreigness, but oddly the father's raised arms seem also to be a gesture of victory.