User blog comment:D. Cello/Assassinews 10/11 -- Desmond's Ancestry Revealed/@comment-76.125.88.188-20111014185158/@comment-90.203.102.58-20111014211221

They are not BLOOD relatives....through a child made by a desendant of Altair, and a desendant of Ezio, they become tied into a bloodline that creates Desmond