Because marriage between close relatives will be bad for future generations, some young people who fall in love with close relatives such as cousins may often have such a question in their hearts. Will marriage have a bad influence on future children? In other words, will you have children with genetic diseases or congenital malformations? If possible, what are the chances? They often come to the doctor with these questions for guidance. Will consanguineous marriage have a bad influence on future generations? This question has been debated. In ancient times when human civilization was uncivilized, consanguineous marriage was very chaotic, with not only collateral blood relatives, but also lineal blood relatives. The rulers of ancient Egypt believed that only royal marriage could keep the purity and nobility of royal blood, so most of the people who got married were brothers and sisters. However, people draw a conclusion from countless facts that the marriage fertility rate of closely related men and women is low, the mortality rate of offspring is high, and congenital malformation and hereditary diseases often occur. In modern times, a large number of data prove that the incidence of dementia children is 150 times higher than that of non-consanguineous marriage, and the neonatal mortality and disability rate are more than three times higher than that of non-consanguineous marriage. It has also been reported that the number of children married by close relatives who died before the age of 20 reached 13.9%, while the number of children married by non-close relatives was only 1.7%. A large number of facts have proved that consanguineous marriage is not good for future generations and should be banned. Therefore, Article 6 of China's new Marriage Law clearly stipulates that lineal blood relatives and collateral blood relatives within three generations are prohibited from getting married. Close relatives refer to people who are related by blood, more precisely, people who are not too far away from their ancestors, usually dating back to three generations ago. Why does consanguineous marriage increase the incidence of genetic diseases in offspring? This should be explained from the perspective of genetics. The inheritance of organisms is accomplished through the transmission of information by genes, which are the material basis of inheritance and passed on to offspring through germ cells (sperm and eggs), so that parents' traits can be expressed in offspring. Each of us has about 50,000 genes, half of which come from our father and the other half from our mother. That is to say, there are 1/2 genes that may be the same between each child and parents, so there are 1/2 genes that may be the same between brothers and sisters. But there are 1/4 possible similarities between grandchildren and uncles. Similarly, there is a possible similarity of 1/8 between cousins. The pathogenic genes of some genetic diseases are recessive. If one parent carries this gene and the other parent does not, the pathogenic gene can be covered up, so the offspring will not get sick. Only when both husband and wife carry this recessive gene will their offspring get sick. As mentioned above, when close relatives get married, the possibility of both parties carrying the same gene is obviously greater than that of the general population. Taking albinism as an example, the disease is characterized by the whitening of skin and hair all over the body. The frequency of carrying this pathogenic gene in the population is 1/50. If the relatives are not married, the probability of the offspring getting sick is110000. If cousins are married by close relatives, the probability of offspring getting sick is11600, which is more than 6 times higher than that of close relatives. At present, autosomal recessive genetic disease 1232 has been found. Besides albinism, other common diseases include congenital deafness's disease, microcephaly, phenylketonuria and galactosemia. Inbreeding will not only increase the incidence of recessive genetic diseases, but also increase the incidence of polygenic genetic diseases, such as hydrocephalus, spina bifida, anencephaly, schizophrenia, congenital heart disease, epilepsy and so on. As can be seen from the above information, the adverse consequences caused by consanguineous marriage are scientifically based. With the improvement of cultural living standards, people have a deeper understanding of the prohibition of consanguineous marriage, which has been accepted by most people. However, there are still a few areas where the custom of marriage still prevails. There are also some people who give the opposite example. For example, some people say that Darwin, a British scientist in the19th century, is a descendant of a close relative. No bad consequences were found in him, and he was smarter than the average person. But these people don't know that Darwin gave birth to 10 children after marriage, of which 3 children died early and 5 children were infertile for life. Indeed, not all offspring of close relatives have mental retardation and genetic diseases. On the contrary, the offspring of consanguineous marriages are not absolutely normal, but only probability. Some young people, cousins since childhood, have established love relationships, knowing the risks, but insisting on getting married by luck. We hope these people believe in science, think about the happiness of their families and the health of future generations, and also think about improving the quality of our nation. Don't take this risk, or they will make a big mistake and regret it.