The irony of identity
The central irony is the one implied in the title, Mulberry and Peach, because Mulberry's self surprises her with a whole different construct than the one she believes herself to be. Her opinion of self is shaped by culture, by role, and by her family's expectations, but ironically, that identity would kill her in America, because she won't adapt well. Ironically, she has to expand her identity quickly, so quickly, she names her instinctual responses "Peach." Ironically, she believes that her identity does not contain Peach, but obviously, it does.
The irony of expatriation
To be expatriated from one's home country means to leave without intending to return, which is the only option left to Mulberry after witnessing the horrific extent of Chinese corruption. She leaves, but she doesn't want to leave. She'd rather stay and be Chinese forever, but instead she becomes expatriated involuntarily. Is America automatically "home" to her? No, ironically, she is without a home, emotionally.
The irony of time and progress
Although parents and communities help to pass along traditional points of view, which help Mulberry in her Chinese life, there is an irony about the need for change, both in China and in America. Clearly, not all tradition deserves to be upheld. For instance, Peach is insistent about feminism. She feels that to move forward in time should include abandoning the stupid constructs around gender that kept her so tightly cloistered before.
The irony of gender role
Gender ends up having almost nothing to do with the plot. Being a girl didn't spare Mulberry from horror, it didn't spare her from abduction and arrest by a government conspiracy, nor did it spare her from the emotional heartache of being expatriated. Gender doesn't lower the difficulty of life for her, so if she is asked to handle the same emotional difficulties as a man, why should she not also be entitled to the authority and command that comes from suffering and experience? Her understanding of gender must grow with feminism.
The irony of sexual inhibition
When she is behaving according to the rules and logic of her instincts, she finds an animal compulsion to enjoy herself sexually. Ironically, the only reason she feels shame about sex at all is because she was taught to, but by rejected the ideas of yesteryear, she realizes that, although feminism is a much needed change, she is already free to enjoy herself without anyone's moral permission. She is free from the grips of shame whenever she is being indulgent and instinctual.
