A escolha foi dada aos filhos de Eärendil
No final da Primeira Era, havia dois meio-elfos na Terra-média: Elrond e Elros, filhos de Eärendil. Como eles pertenciam a ambas as raças, os Valar lhes deram a escolha:
Now Elros and Elrond his brother were descended from the Three Houses of the Edain, but in part also both from the Eldar and the Maiar; for Idril of Gondolin and Lúthien daughter of Melian were their fore-mothers. The Valar indeed may not withdraw the gift of death, which comes to Men from Ilúvatar, but in the matter of the Halfelven Ilúvatar gave to them the judgement; and they judged that to the sons of Eärendil should be given choice of their own destiny. And Elrond chose to remain with the Firstborn, and to him the life of the Firstborn was granted. But to Elros, who chose to be a king of Men, still a great span of years was allotted, many times that of the Men of Middle-earth; and all his line, the kings and lords of the royal house, had long life even according to the measure of the Númenóreans. But Elros lived five hundred years, and ruled the Númenóreans four hundred years and ten.
The Silmarillion: Akallabêth
Page 261 (George Allen and Unwin 1977 hardback edition)
Uma vez que Elros escolheu ser mortal, não foi possível para seus descendentes escolherem o contrário.