É claramente declarado várias vezes no Silmarillion que apenas Ilúvatar pode criar vida.
No capítulo 2 de "Quenta Silmarillion" ("De Aulë e Yavanna"), Aulë cria os anões, mas Ilúvatar o repreende:
Why dost thou attempt a thing which thou knowest is beyond thy power and thy authority?
No capítulo 3 ("Da vinda dos elfos e do cativeiro de Melkor"), a criação dos Orcs é explicada:
...all those of the Quendi who came into the hands of Melkor, ere Utumno was broken, were put there in prison, and by slow arts of cruelty were corrupted and enslaved; and thus did Melkor breed the hideous race of the Orcs in envy and mockery of the Elves...
For the Orcs had life and multiplied after the manner of the Children of Ilúvatar; and naught that had life of its own, nor the semblance of life, could ever Melkor make...