\"Three generations\" is calculated by how

&Nbsp;   \"within three generations of\" How is calculated? Used to represent the genetic relationship between close and distant distance from generation to generation, \"generation smaller the number, the closer the relationship between, on the contrary,\" \"the larger the number, the relationship further. This is not difficult to understand what we are \"three generations\". Less than three generations is calculated: lineal blood kinship within three generations are from the same grandparents (grandparent) lineal blood kinship. Within three generations of grandparents (grandparent) for generations, parents for the second generation, who is a third generation, in a family, and formed a grandchild (grandparents and grandchildren, grandparents and maternal grandchildren) and the relationship between parent and child relationship. China\'s marriage law provisions on the prohibition of marriage, lineal blood kinship is unlimited, is prohibited. Prohibition of marriage between lineal blood kinship, not only required by law, is the world\'s general orders. Three generations of blood is the next coming from within the same Department of blood next to the grandparents, grandparents. Less than three generations of blood including: 1. brothers and sisters. Includes full-blood siblings of the parent tongmu, half-sister or uterine half-blood brothers and sisters. 2. the primary, and uncle, and aunt and nephew, and cousin, uncle, and aunt and niece, and niece. 3. the Hall brothers and sisters, cousins. According to China\'s marriage law stipulates that where the next blood within three generations, includes the same seniority and different persons, are prohibited marriage. Provided for in the current marriage law prohibited marriage of the next line of blood within three generations, is to table in the supplementary regulations prohibiting marriage.