And yet, my mother and her family are red-haired going back many generations, my children's father has red-haired uncles/aunts, and none of their descendants- children/grandchildren/gt grandchildren are red (though my son was born red, went blond and stayed that way, but with a red beard). Most of the Spencer grandchildren are blond, though Lady Sarah's son is red. None of William's kids is red. The chances of their having two red-haired children are very, very slight. None of the Markles or Raglands have claimed red hair to the best of my knowledge. Very interesting to hear from a geneticist who really knows about this stuff.
So what conclusion have you arrived at?