Originally Posted by Alison H
Henry VI only had one direct descendant though ... and even that's debatable as a lot of people think Prince Edward was actually the son of one of the Beauforts!
If we're arguing that Catherine de Valois introduced insanity to the BRF then the fact that she mothered both Henry VI and Edmund Tudor (who then fathered Henry VII), then she may have also passed on said insanity to her younger son, who could have passed it on to future generations of the BRF. Henry VI may have had only 1 direct descendant, but every monarch of the BRF since Henry VI except for the Yorks have been descended from Catherine de Valois.
Of course this is based on the idea that Catherine gave Henry VI genes for insanity (which she also then have Edmund Tudor), and that the insanity displayed in later members of the BRF is caused by the same thing that caused Henry VI's insanity. The mental instability seen in the Hanovers is commonly attributed to being porphyria (although it's not proven to such), and it's believed that some of the Stuarts had it as well - going back to James V of Scotland. From there we can say that if they actually had porphyria that got passed on a bit, was it caused from James V's Stuart father, James IV, or his Tudor mother, Margaret Tudor. Only one was descended from Catherine de Valois.
As to whether or not Prince Edward was descended from Henry VI, the claims that he wasn't were rumors spread by the Yorks - not exactly credible sources. Really it just seems like an attempt at slandering the Lancasters in general and Margaret of Anjou specifically. It should be noted that Henry's mental breakdown came after the conception of Edward, and the announcement of the pregnancy strengthened the Lancaster court. This can be seen as comparable to the rumours that the Old Pretender wasn't actually the son of James II but rather an imposter smuggled into the birth chamber in a warming pan.