Using a variety of standards (height, age, education, salary, etc.), the sexist marriage grades in China are extremely important. Indeed, they determine your choice of a mate since the superior gender (the male) cannot marry a female from the same class. Thus, A grade men marry B grade women, B grade men marry C grade women, and C grade men marry D grade women.
That means it's just tough luck for the A grade women and D grade men.
It's just another of the culturally destructive combinations of Buddhist traditions and Communist tyranny -- a combination that also created China's barbaric one-child policy, a policy rife with forced abortion, massive sex-selection abortion, and mistreatment of women in general.
And yet that's still not all. Here's Marcus Roberts with more.