Why did the ancient cousins marry their cousins, but most of the children were normal?

In ancient China, consanguineous marriage prevailed, and different surnames between cousins were the most common. In ancient times, it was forbidden to marry with the same surname, but there was no excessive demand for intermarriage with different surnames. First, in ancient times, close relatives got married for the sake of family face. Even if they get married, they may not necessarily have children after marriage. Second, the unhealthy children of ancient royal families will be disposed of or the news will not be spread. Third, the ancient family was huge and the relatives were complex, covering three thousand miles. Although some of them are cousins, they are not related by blood. A natural baby is fine.

As early as the late Paleolithic, consanguineous marriage was forbidden. People have realized the harm of consanguineous marriage to people in long-term practice, so they reject marriage between peers and prohibit marriage between brothers and sisters. Exogamy has also appeared. With the growth of population, the clan scope has expanded, and the situation of consanguineous marriage has gradually appeared. In ancient China, the same surname never married, and the custom of the same surname never married by the Han people also continued.

In ancient times, cousins married and most of the children born were normal. This view is wrong. Modern research has found that most cousins are healthy, so no matter ancient or modern, most cousins are normal. In many ancient examples of consanguineous marriage, it is not difficult to find that they are all cousins.

The paternal line is the hall, and the maternal line is the dining table. The ancients believed that the blood flowing from a child belonged to the father, and families with the same surname could not be chaotic. The ancients always adhered to the concept of kinship, while cousins are the combination of two families, which deepen family relations with blood ties and maintain family stability and interests for a long time.