Primogeniture has been sorted here in the UK ... but I understand only 3 of 15 Commonwealth Countries have ratified
Interesting . . . here's a possibility. If a (misogynist) Commonwealth country
didn't ratify, and the firstborn was a girl, then although she would idc become Queen of England and other stuff, her younger bro would presumably become King of those countries still believing in male primogentiture.
A boy would be easier all round.