In Rural China, where the male/female population is way out of wonk because of Communist social experiments, multiple brothers will all marry the same woman. They go to bed with her one by one, tossing a load off in her. However, only the oldest brother is ever "the father" to any kid, regardless of who actually sired the little nong because it makes family politics easier.
Now, imagine this: some illiterate soybean dirt farmers from the fourth world are gang banging a woman and have managed to figure out the politics behind this whole familia structure when these high falooting NY honkies can't even decide on what to call themselves.