Viserys proclaimed Rhaenyra his heir and she is older then Aegon.
When he dies Rhaenyra and her half-brother Aegon II fight for supremacy. However he continues proclaiming her heir despite having sons from his second marriage. Viserys I declares his daughter from his first marriage, Rhaneyra, as heir.
The male-less society shown actually does seem pretty awful, thus implying the pro-men character is correct. John Wyndham tries to present this in the novella "Consider Her Ways" by asking the question, "Would women be better off if there were no men?" Two characters argue over this, with neither presented as being irrational or clearly wrong.Black Crown: In the story 'Schism', both King Flavius and Lord Corrigan have a point depending on how you view a government's duty to its people.