Hello, doctor! I want to ask if close relatives can have children when they get married? First of all, the relationship is like this. My grandfather and my girlfriend's great grandmother are close brothers and sisters. Is such a relationship close relatives? Can you get married and have children?
There are recessive genes in each family. The closer the relatives of two families are, the greater the probability of two identical pathogenic chromosomes colliding in the future, and the higher the probability of genetic diseases in the offspring. In principle, your grandfather and your girlfriend's great grandmother belong to the fourth generation and do not belong to close relatives.
The relationship you mentioned belongs to close relatives. But it's far away. There's nothing wrong with having children. But there is no guarantee that the child will never have a problem. If your grandfather has a genetic disease in his family, it may also be inherited from your children.
According to your situation, there should be some recent characteristics. If you get married in this case, there should be a characteristic of close relative marriage. Therefore, marriage is not recommended in this case. If you want to have children, you can go to the genetics clinic for professional consultation. The probability of suffering from genetic diseases is higher.