Zhang Qiang and Li Jing have always been healthy and have not undergone genetic counseling and regular prenatal checkups before pregnancy. After the birth of the fat and white son, the family was overjoyed. However, when the son was almost a week old, it was found that he could not sit up, his face also showed double-eyed hanging, often spitting out his tongue, and his reactions were slow, and the couple rushed to the hospital for examination. With this result, Zhang Qiang and Li Jing were grief-stricken. In China, congenital dementia accounts for 1/750 of the total population, and 2% of newborns are born with congenital anomalies every year. Every couple preparing for a new life must want their child to be healthy, smart and beautiful. However, if a deformed or demented child is born, not only are the parents greatly stimulated, but the child itself suffers untold pain. So, how do deformed children and demented children arise? Why did Zhang Qiang and Li Jing give birth to an unhealthy child? We know that hereditary and congenital factors are the most important among the factors affecting the quality of the population. 1, hereditary factors refers to the parents’ germ cells, that is, sperm and eggs carry disease genes, and then passed on to their children and caused by the disease, and these children will also pass the disease to the next generation after marriage. These diseases are passed from one generation to the next, and are medically known as genetic diseases. Genetic diseases are characterized as congenital, lifelong and hereditary, and can affect the health of several generations. Usually, most parents with obvious hereditary diseases undergo genetic counseling before conception to prevent the birth of a child with the disease, but there are many genetic diseases that are recessively transmitted, i.e., one or both parents may carry the disease-causing gene without the parent or predecessor having direct disease, and the child may develop the disease. Therefore, for some healthy people with risk factors and normal phenotypes, it is necessary to conduct the necessary genetic counseling and testing. The targets of genetic counseling include: couples who have given birth to children with genetic or congenital malformations; couples who have a family history of genetic diseases or one of the couples has a genetic disease; couples who have had unexplained habitual miscarriages, premature births, or stillbirths, senior pregnant women over 35 years of age; pregnant women with heart disease, kidney disease, diabetes, etc.; couples who have taken or been exposed to chemical drugs or radioactive substances and other harmful substances that are likely to cause malformations. The farther apart the children are, the smarter they are, such as those born to southerners and northerners, Chinese and foreigners, why is this? Because men and women who intermarry in too small a circle still carry a certain percentage of the same genes. Although some are not related, but generations of intermarriage, the offspring will carry more and more of the same genes in the body, science called “genetic factor purification”. The increase in the degree of genetic purification will lead to an increase in the incidence of genetic diseases. When two men and women who are not related by blood and are geographically distant marry, there is less chance of genetic purity, so there are fewer offspring with recessive genetic diseases, and the child’s physique and talent are significantly better than those of the parents. Therefore, when people of different races and regions marry each other, their offspring will be smarter and more fit than their parents. We know that pregnant women who are 35 years of age or older are more likely to have offspring with chromosomal disorders. This is because the quality of eggs decreases with each passing year and the possibility of chromosomal variation in the egg cells increases. Therefore, the best age to have a baby is 24-29 years old for women and 26-35 years old for men, when both spouses are physically mature, hormonal secretion is strong, and the fetal development environment is good for fetal growth and development. 2, congenital factors usually refers to the child’s embryonic development stage by the influence of various harmful factors so that cell chromosome aberrations, or harmful substances inhibit the mitosis of cells, preventing the normal differentiation and development of the organ fetus and produce malformations. Common teratogenic factors include microorganisms (such as viruses), drugs and certain chemical agents, certain metals and radioactive substances, etc. We know that during pregnancy, especially in early pregnancy, infection with viruses and other microorganisms can affect embryonic development, because at this time the organ differentiates and develops rapidly and is most sensitive to external teratogenic factors. The teratogenic effect of certain drugs has been agreed by most people, and some special physiological changes of women during pregnancy make their absorption, excretion and detoxification functions of drugs different from those of non-pregnant women, and many drugs can enter the fetus through the placenta, while the liver function of the fetus is not yet perfect and the kidney excretion ability is poor, which can easily cause accumulation of poisoning and lead to developmental malformations or chromosomal mutations. Therefore, pregnant women should not take drugs that may cause malformations at will. If a pregnant woman is suffering from a disease that requires long-term medication, she should consult a doctor before planning to become pregnant, determine whether she can become pregnant and the appropriate time to conceive under the guidance of a doctor, and work closely with the doctor during pregnancy. The role of environmental pollution, electromagnetic and video pollution should not be underestimated. The effects of radiation on the embryo and fetal development have long been recognized by the medical community, and it is also important to stay away from microwave ovens, computers, cell phones and other items with strong electromagnetic radiation. Some special jobs: frequent exposure to lead, cadmium, mercury and other metals can increase the likelihood of miscarriage and stillbirth in pregnant women, so women in these occupations should be temporarily transferred to other jobs when considering conception. 3, the causes of fetal malformation in addition to the above-mentioned reasons, but also related to diet, living habits and the season of pregnancy, etc.. Pregnant women who love to be close to cats and dogs are easily infected with toxoplasmosis, which directly affects the development of the fetus and poses 10 times greater risk of malformation than uninfected pregnant women; do not wear heavy make-up during pregnancy; toxic substances such as arsenic, lead and mercury contained in cosmetics are absorbed by the skin and mucous membranes of pregnant women. After that, they can pass through the blood-fetal barrier and enter the fetal blood circulation, affecting the normal development of the fetus. It is better to choose the season of pregnancy in late summer and early autumn to facilitate the growth and development of the fetus. A good physical and mental state will have a beneficial effect on the reproductive cells of both men and women, as the fertilized eggs obtained at this time are also of the highest quality. Avoid conception during solar magnetic storms, earthquakes, solar and lunar eclipses, and full moon nights, when X-rays and solar flares can reduce the quality of human sperm and egg cells. If primitive human beings can only rely on the natural law of survival of the fittest to maintain the continuity of life, modern human beings are fundamentally different, i.e. the whole society works together to create a public opinion environment of eugenic civilization and a good natural ecological environment. To prevent the birth of deformed children and demented children, we should also avoid marrying close relatives, take premarital medical checkups seriously; make good preparations before pregnancy, establish a perinatal health card immediately after pregnancy, conduct regular checkups and prenatal diagnosis when necessary, and try to eliminate the birth of deformed children and demented children.