Ancestral fault (Greek προγονικὸν ἁμάρτημα, προπατορικὸν ἁμάρτημα) is the doctrine that the sins of the forefathers lead to punishment of their descendants. In Christian hamartiology, the concept is also known as ancestral sin (προπατορικὴ ἁμαρτία or προγονικὴ ἁμαρτία).
Martin West (1999) draws a distinction between inherited guilt (ancestral fault or ancestral sin in the narrow sense) and ancestral curses (in the form of genetic corruption or general "persistent but unexplained adversity").
The most detailed discussion of the concept is found in Proclus' De decem dubitationibus circa Providentiam, a propaedeutic handbook for students at the Neoplatonic Academy in Athens. Proclus makes clear that the concept is of hallowed antiquity, and making sense of the apparent paradox is presented as a defense of ancient Greek religion. The main point made is that a city or a family is to be seen as a single living being (animal unum, zoion hen) more sacred than any individual human life.
The doctrine of ancestral fault is similarly presented as a tradition of immemorial antiquity in ancient Greek religion by Celsus in his True Doctrine, a polemic against Christianity. Celsus is quoted as attributing to "a priest of Apollo or of Zeus" the saying that "the mills of the gods grind slowly, even to children's children, and to those who are born after them." The idea of divine justice taking the form of collective punishment is also ubiquitous in the Hebrew Bible, e.g. the Ten Plagues of Egypt, the destruction of Shechem, etc. and most notably the recurring punishments inflicted on the Israelites for lapsing from Yahwism.