Marriage between close relatives, called incest or incest, is prohibited in all states and is condemned in all cultures as one of the most disgusting acts.
The ancient Greek myth of Oedipus, the Karelian-Finnish legend of Kullervo - in all these stories incest appears as a serious sin, incurring a curse, and sometimes not only on the one who sinned, but also on others. It is noteworthy that for both heroes the incest was not conscious - Oedipus did not know that Jocasta was his mother, Kullervo did not know that he had fallen in love with his sister - but this does not save anyone from retribution.
Modern Prohibition of Related Marriages
Forbidden incest in the modern world is based on genetics.
Defective genes that carry deafness, blindness, cystic fibrosis and other congenital pathologies are, in most cases, recessive. In other words, for such a gene to manifest itself, it must be inherited from both parents. Otherwise, a person is born a carrier of a genetic defect, but not sick.
In a family where there is a defective gene, all people are carriers of it. If a man and a woman from such a family marry, the probability of having a baby with a double defective gene increases dramatically. Of course, during ordinary marriage, it happens that there are two carriers of the defective gene, but the likelihood of such an event is negligible.
Thus, the prohibition of closely related marriages helps prevent the inheritance of genetic pathologies.
