"Or simply a descendant in the female line," pointed out Dumbledore. "For a recent example, consider Draco Malfoy, who is technically in the line of inheritance for both the Houses of Malfoy and Black, because of his mother. This is not common, but it does happen. However," he frowned. "The House of Potter is, historically, not prone to large families. James Potter was an only child, and so were his father and grandfather. Indeed, judging by the genealogy, they suffer a similar problem to that of the Weasley family, the tendency not to have female children." The Headmaster tapped his fingers absently on the table, faintly curious. "Someday I am going to have time to investigate that phenomenon."