And most importantly, they shun marriage.
Yes. No marriage at all. So where do the kids come from?
I guess some of you may be processing your sordid imagination by now but no, there is no incest involved.
Women may also change partners as often as they like, and promiscuity carries no social significance. Most of the women, however, don't change walking-marriage partners very frequently. And they rarely carry on more than one romantic relationship at a time.
Instead the men help to look after all the children born to their own sisters, aunts, and other women of the family.
Rather than one father with a kid, it will be four or five uncles. That father role is shared among a number of people, and these are very large extended families. They think that if you father a child with another woman, you can never be absolutely sure that the child really shares your genes, but if your sister has a child, you can be 100 percent sure that the kid shares some of your genes.
If the father wishes to participate in his child's upbringing, he signals his choice with gifts to the mother’s family, and stated intention to do so. This brings him a certain status within the family, but by no means a claim of kinship.
So, to all men out there, there'd be no Fathers' Day if you're a Mosuo man, and you would have no part to play in your children's lives apart from inseminating their mothers.