Renowned Russian horticulturist Michurin conducted extensive experimental research that demonstrated the principle: "breeding with distant relatives produces good offspring, while breeding with close relatives produces monstrosities." Physiologists have also found that even in seemingly healthy families, there can still be children born with physical or intellectual developmental issues. These children often lack vitality and may die in early childhood. One of the main reasons for such tragedies is consanguineous marriages.
As a result, civilized nations generally prohibit marriages between close relatives, including direct ascendants and descendants, as well as between full siblings, half-siblings, or those with the same father or mother. This is aimed at preventing the birth of offspring from incestuous relationships. While marriages between more distantly related relatives, such as between uncles and nieces, cousins with the same great-grandparents, or aunts and nephews, are sometimes considered acceptable, the likelihood of offspring having physical and intellectual developmental defects remains high in these cases. Ultimately, the law does not recognize marriages involving individuals with mental illnesses or disabilities that render them incapable of living independently.
