I recently came across an article that asserted that Henry VIII's reproductive woes were caused by his having Kell positive blood (a rare blood mutation). This was supposedly inherited from his great-grandmother, Jacquetta of Luxembourg. If this were true, then it would stand to reason that Henry's other male relatives on his mother's side would have had the same problem. Did they? I recall that Henry Stafford, Duke of Buckingham, had numerous children by his wife, Catherine Woodville, who was Queen Elizabeth Woodville's sister. Does anyone know how fertile the other Woodville marriages were? I do remember that Anthony Woodville had no children..