Closely related marriages and mental disorders in offspring

Closely related relationship (BS) is a reproductive relationship between partners who have one or more common ancestors, an increased number of identical genes and, accordingly, a higher risk of hereditary diseases of gene origin for the offspring. Traditionally, many peoples support and welcome the practice of creating a new family within a certain clan, nationality or religious group. The common ancestor is often itself a descendant of BS, etc. In such cases, the "progenitor effect" can be noted: a rather rare hereditary disease or a disease with a genetic predisposition will occur much more often than in the population and will manifest itself in many family members over several generations.