She won't officially be Princess of Asturias until age of majority which is quite a few years away. Plus the fact that Letizia had an awful time bearing and delivering children really doesn't vote well for her having any more, especially as she gets older.I guess they are taking for granted that Felipe and Letizia won't have any more children. What if Letizia, who is already 41, unexpectedly gets pregnant and gives birth to a baby boy ?
I know that scenario is very unlikely, but, formally speaking, I don't think a decision on Leonor's becoming Princess of Asturias should be made before the constitution is officially amended to eliminate male-preference primogeniture.