The cause and effect word in sentence (3) is result. The word result can mean "because of this...this is the result." In this text, sentence (1) explains the issue/cause, the Chinese policy that only allows one child per family. And as a result horrible effects take place. Sentence (2) expresses the first effect and sentence (3) uses the word result to signify that this is an effect of the cause, but more specifically, the sentence uses the phrase another result to imply that this is an effect on top of other effects.