I think there is more to it than just a fad, it is that however, Propaganda has a lot to do with it also like the ads with mixed family seen daily on television....the butchy wife with the dumb husband, even more troubling the ads begging you to live beyond your means....big homes, furniture, clothes, vacations....
Could be any number of things. Diet, trend, programming, toxins from pollution, fluoride, HFC, inoculations, microwaves, rap music, antibiotics, less contact with the soil, the Russians, Glutin, peanuts, fecal matter, cartoons, too many rats in the cage... gestational. The possibilities boggle the mind.