Important Note: Unlike Holy Fury, King/Queen's Kin is a mandatory optional dynasty rule that you can never avoid and it is required to make a matrilineal marriage match. If your intended heir is unwilling to be matrilineally married, you must select a new heir.
Note that the King/Queen's Kin game option is not a classic matrilineal option since there is no actual female ruler to inherit. It does make an excellent matrilineal option and can be a great way to make a personality conflict. It is also a good normal clan conflict option, should it ever occur.
Matrilineal and Multigenerational:
Matrilineal and multigenerational means that the heir inherit the same lands as their mother. If they are not half of the same name as their mother, their mother is usually relevant to their claims. Although important, land claims are not always the most important. The heir may be important because of their bloodline, but if their mother is not also important, they may be passed over.
Matrilineal and Single:
If your heir is of a foreign ethnicity, or if the duke/duchess is of a foreign ethnicity, make sure to check if they are friendly to your realm. If so, you may want to find another heir. 827ec27edc