Consanguineous marriage is the intermarriage of immediate family members within three generations; the closer the blood relationship, the greater the risk of hereditary diseases, and consanguineous marriage only affects the next generation of the consanguineous couple. Marriage refers to the intermarriage of direct relatives within three generations. Due to the existence of common ancestors within three generations, the closer the blood relationship of the relatives, the combination of recessive genes controlling the same hereditary diseases, the hereditary traits controlled by these genes are more likely to be expressed, and the next generation is more prone to the occurrence of some hereditary diseases, such as fetal malformations, mental retardation, and miscarriages. Marriage is strictly prohibited between blood relatives in the direct line and blood relatives in the collateral line up to the third generation, and in the case of consanguineous marriage, it will only affect the next generation, which, as long as it does not continue to have consanguineous marriages, will not be affected by the next generation.