Little Emperor Syndrome is a colloquial term for an 'illness' affecting the second generation who are under the One Child Policy. These children generally have 4 grandparents, who only have 2 children between them, i.e. the little emperors parents. These parents only have one child. This also became known as the 4-2-1 problem.
The second generation children normally have 4 grandparents and 2 parents but since they are the only heir they get lavished with attention and special treatment. With no brothers or sisters the child generally becomes selfish and unprepared for the outside world. There are also thoughts that with all 4 grandparents alive it leads to children being over fed with treats and snacks- often leading to obesity.