How to understand the traditional Chinese ideology of "unfiliality is three times as great as having no offspring"?

"There are three filial piety" is from "Mengzi? Li Lou Shang". The original text is: Mencius said: "There are three unfilialities, and the absence of a descendant is the greatest. Shun married without telling, for no queen. The gentleman thought that the Judge also told."

It is said that Emperor Shun did not inform his parents when he married Yao's two daughters, this is because he was away from home and had to have a son to carry on the family line, so his behavior was filial, not unfilial.

There are three kinds of unfiliality, according to the ancients: first, not correcting the mistakes of one's parents; second, not working hard enough to keep one's parents in poverty; and third, not having a son to carry on the family's legacy.

In the traditional concept, the family inheritance is the first important, is also the most important evaluation of filial piety standard. Analogous to the ancient repudiation of the wife has "seven out of" the saying, ranking first is "childless". This is the most important thing in the traditional concept of the birth of a child.

Now and ancient times are different, celibacy and Dink family more and more, but this kind of thinking is still the mainstream of society it