When Western people graduate from college and/or get their first jobs, they typically move out of their parents' house and live independently. In the United States, for example, it is generally a social stigma to continue living with one's parents after reaching adulthood.
In China, however, most young people will live with their parents until they get married. Many couples will even continue to live with one set of parents after marriage. When the young couple has a child, at least one pair of grandparents will live with them or very close so that they can help them raise the child.
Unlike their European or American counterparts, a young Chinese person is rarely financially independent from his family. Many young people, upon graduation from school or university, will give a portion of their salary to their parents. Thus they contribute to the household income since their parents are paying for housing, utility and food bills. Some will turn over their entire salary to their parents and will receive an allowance back for personal spending.
The parents, in return, must save enough money to pay for their child's wedding gift. For sons, they are obligated to buy an apartment when he gets married; and for daughters, many will buy a car for the new couple. This is why many couples in large Chinese cities like Shanghai prefer to have daughters rather than sons, because the financial burden of having a son is much greater (in rural areas of China, there is still a strong preference for sons). Furthermore, they will be expected to raise their grandchildren, because nearly all Chinese women will return to work full time after the baby is born. As the parents grow older, the young couple is expected to take care of them in their old age.
When Chinese families move abroad, many of them still retain this close-knit family relationship and help their children financially. Among well-established immigrants, parents often buy their children their first house, so that they will not be burdened with mortgage payments. In return, the parents can visit their children whenever they want to, and can stay for months at a time. If a young couple is living abroad when they have a child, and their parents are still living in China, they will typically either send the child back to China for the grandparents to raise, or would ask the grandparents to come abroad to take care of the baby.
(selected from 101 Stories for Foreigners to Understand Chinese People by Yi S. Ellis and Bryan D. Ellis, published by China Intercontinental Press in 2012)