Due to its unrivaled properties, the MOSFET has become the dominant device species. However, in spite of its remarkable adaptability to the scale down evolution, it will have to face practical limits around 30nm gate length. Below that length, innovative devices, based on quantum mechanical effects, are already emerging. After optimization, they could compete with the MOSFET, transposing to devices the struggle for life theory from Charles Darwin. New devices and possible applications are reviewed. In addition, trends about the chances of success of the challengers are discussed.