Dumarest encounters several characters in his travels who believe that an individual's ability to consistently survive mortal danger and long odds is not merely an amalgam of separate beneficial traits, but a specific and unique genetic factor (Yendhal in Book 7 - Technos, Charisse Chetame in Book 23 – World of Promise, and Shakira in Book 28, Melome).  Naturally, they inevitably come to conclude that Dumarest embodies the ultimate expression of this gene.