Mosuo families tend to trace their lineage through the female side of the family (they may sometimes not even know who the father of a particular child is, so tracing through the paternal line is impossible). Families that don't have a female to take the role of a family's matriarch may "adopt" a woman from another family, and she will take over as head of the house when the current matriarch dies. She, and her offspring, will be included in the ‘family genealogy'.