As we all know, China people have the custom of getting married, that is, on the wedding day, the groom (or the groom's family) will take the bride to the ancestral grave to "report" to the ancestors, commonly known as "calling the door", which actually includes the bride's position in front of the groom's grave, although the bride's position is "sojourning" in the husband's position.
It can be understood that the influence of ancestral geomantic omen on future generations is based on "father as the main line and mother as the constituent element"; In other words, the influence of ancestral graves on future generations is based on "every small family" of future generations, and the influence is exerted step by step (that is, future generations).
In ancient society, a man's "wife" and a man's "concubine" were both recognized by "commanding ancestors", so the geomantic omen of ancestral graves also affected the fate of the boy born to this man's wife or concubine. On the contrary, as an illegitimate child (just a boy), because his mother is not recognized by the ancestors of his own biological father (that is, the lover of this illegitimate child's mother), the ancestral grave of this illegitimate child's biological father's house will not affect his fate. At the same time, as an illegitimate child, the ancestors of her mother's husband's family who is going to marry also disown him. So people often call illegitimate children "illegitimate children", that is, those children who have no ancestral graves to look after.
For adopted children (only boys), their fate is still taken care of by their biological fathers' ancestral graves, which is why many adopters in China still take their fathers' surnames. According to the traditional folk custom, the adopter should be buried in the ancestral grave of the adopted family after death, but this is only a form. The ancestral grave of the adopted family will still have no influence on the descendants of the adopter, which is essentially equivalent to the adopter moving out of the ancestral grave of his biological father.
As a remarried woman with a child (only a boy), as long as the child is born after the woman legally marries her husband, the fate of the boy will still be affected by the ancestral grave of the biological father's family; As a remarried man, no matter whether the children (only boys) follow their father or mother after divorce, the ancestral grave still affects the fate of their children.
In short, we should remember two main points: the first point is that only boys are considered when looking at the ancestral graves; Second, the fate of children born after the marriage of Ming media is always influenced by the ancestral graves of their biological fathers. On the contrary, the children married by the Ming media, whether born before marriage or after extramarital affairs, are regarded as "illegitimate children" because their fate is not taken care of by any ancestral graves.