In some parts of India, to this day, there's a culture wherein when a woman marries a man she automatically becomes the wife of the whole family (father and brothers), hence they can sleep with her.

In an area of China there's no such thing as marriage, they just sleep around. When a girl gets pregnant and have a baby she takes care of this by herself, no husband. Her siblings and, if she has more child, other children looks after the baby.

Sent from my mind using Telepathy 2