It happened all the time in royal / rich powerful families in...

It happened all the time in royal / rich powerful families in order to keep power within the family.

"Queen Victoria and Prince Albert: Queen Victoria, known as the “Grandmother of Europe,” married her first cousin, Prince Albert of Saxe-Coburg-Gotha.
Their union resulted in the spread of hemophilia—a disorder that prevents blood clotting—through their descendants. Their son Leopold, Duke of Albany, was a haemophiliac, and several of their grandchildren also suffered from the condition"


I never denied that inbreeding occurred in our history.
I know of a bloke who bonked his sister and she fell pregnant; morality aside, the risks to offspring are real.