Really fascinating.

In my corner of the world, there are tribes still isolated in the middle of nowhere. Gov tries to modernize their lives and has issued them documents, but they still prefer to go back to lands where there is nothing (seemingly) but sands and sky.

I have seen some of the tribals when I was in gov office making documents for my son who reached 15 yo. But there is a big difference off course. In the case discussed here it is only one family, not a whole tribe. This has dragged my mind into some area maybe not many members want to head to. Namely: sex. In all tribes we have seen around here or on National Geographic, they had some form of marriage. This is not the case in ONE family where there is only brothers and sisters.

Forty or thirty years is a very long time.
Maybe we can think of stravation and harsh life to be enough to keep them busy , enough to push it aside. But the story says that parents - in this case - had two kids in the wilderness. So the environment wasn't harsh enough to completely wipe out the urge .

Sorry to take the thread in this area.
Just thinking aloud.

And I have seen a film a few weeks ago about some mountain villagers who went to other village to find a wife for their son. Makes me think about this family doing the same.