Looking further into the future, I suppose the eldest daughter of Felipe will inherit the throne after her father. What if Felipe and Letizia have another child and it is a boy? What about the older sisters? (Elena and Cristina) Were they ever in line or since there was a male, it had to be him? I know there are other troubles associated with one of their husbands, but I'm strictly asking about the line of the throne and how it goes.