In a twisted observance of Fathers' Day, we bring you news of matrilineal society of the Mosuo (sounds like How-Sue-Oh) people of the Chinese Himalaya. The agrarian Mosuo are a people that we know hasn't had conventional/formal marriage in a thousand years.
While you're wrapping your brain around that concept, here's more:
The Mosuo practice what they call "walking marriages," where women pair up with lovers and invite them to their homes in the evening only to ask them to leave in the morning.
What? The booty call as the societal function of procreation? Maybe women aren't so different from men after all, eh? ;-)
The Mosuo bear and raise their children, and live their entire lives within homes comprised of their extended matrilineal families. The role of Father is shared by various matrilinially-related male relatives. A child may or may not know the father, either because the mother is still involved with the father or the father does not want to know the child, but the entire culture considers the matrilineal family of first importance because, well, you always know to whom you are related if such things are judged by who's giving birth to whom. The father may or may not have any interest in or responsibility for his own children, but he will have interest in and responsibility for all of the children born to the women of his household.
The Mosuo aren't particularly promiscuous, in fact, many women will pair off only a few times in a lifetime. Serial monogamy is an apt description. There is no such thing as divorce in their culture, because it's not needed. When all property passes matrilineally and all children are in the sole custody of their mothers and her extended family regardless of her relationship (or lack thereof) with the father, divorce never becomes a concept.
Women often head the extended families, and women make most of the business decisions. The political power of the Mosuo tends to rest with the men, balancing the family and business power of the women.
Women maintain their autonomy, men know for a fact that their genes are being passed on (through female relatives), and families are incredibly stable (no divorces, shared custodies, fostering with relatives in another state, etc.), and divorce is a non-item. What could be better?
A short article and 3-minute National Geographic video interviewing several Mosuo people streams here. Wikipedia has a Mosuo entry, YouTube has a 12-minute video about them (too bad the Mosuo weren't subtitled!), and Amazon has a book by a Mosuo woman (with the help of an anthropologist) about her life as a Mosuo.