I wouldn't be so sure of that. For many centuries, inbreeding was an essential qualification for becoming a monarch.
Inbreeding is an essential quality of Islam. Over half of all Muslims are married to their first cousins. As were their parents, grandparents, great-grandparents, and so on for the past 50 or so generations. Now, do you wonder why the only thing that Islam has produced in 1400 years is war and murderers?
I read an interesting book years back (can not remember the tittle) about the Tory remnants remaining in the US after the revolution.
The practice of arranged marriages within families of domestic British descendants still holding land granted by the crown persists to this day.
The book was based on families in Hamilton Massachusetts.
Shocker there.
Yes. May I offer a perfect example of the possible results: Prince Charles and his sister, Princess Anne. Ah, the House of “Windsor”.