So you have three things right there. No one can function without privacy. There's never been a society on the face of the earth that didn't use privacy for certain practices, such as sexual relations.
I had a great story from a very open mother Tuesday morning in Vancouver, who told me that her daughter--16 and brilliant--asked her, “How often do you and Dad have sex?” She looked at the kid and said, “That's private.”
At least I didn't get into your sex life.