In primitive societies twinning raises emotions varying from extreme terror to hope and joy. The first impulse prevailing among the less civilized people seems to be to regard twins as unnatural and monstrous and therefore as portending evil. Accordingly, they must be put to death and the offence repudiated. This negative attitude stems from a series of explanations which can generally be connected with the widespread belief in superfetation and double paternity. In a few cases only, would the custom of sacrificing twins arise from economic necessities. However, in many agricultural primitive tribes, twinning is regarded as a happy event. In this case, the worship of twins entrusts them namely with power over water allowing to confer fertility to the soil and also to women and animals. In the past, the mother of twins was often executed with her offspring or simply banished. In many tribes, she is still compelled to go through elaborate purification in order to forestall the evil omen. If twins are welcomed, their parents are similarly respected as they symbolize the fertility power of the clan. Superstitions and myths pertaining to twinning are universal and often present converging features among cultures without mutual contact. This would point to the twin cult as one of the earliest religious beliefs of mankind.