What is a genetic test? What are the precautions? A gene is a DNA or RNA sequence that carries genetic information, also called a genetic factor, and is the basic unit that controls genetic traits. Genes control the performance of traits in individual organisms by directing protein synthesis to express the genetic information they carry. Thus, children look or have a personality similar to that of their parents. Normal genes in the human body are also divided into different genotypes, or genetic polymorphisms. Different genotypes have different sensitivities to environmental factors, and sensitive genotypes can cause disease in response to environmental factors. In addition, diseases that are directly caused by abnormal genes alone are called genetic diseases. Genetic alterations are not always due to heredity. This means that genetic mutations (deletions, duplications, point mutations, etc. can be understood as genetic defects) are not always passed on to the next generation. There are three types of genetic alterations that cause disease: 1) postnatal genetic mutations (often without a family history); 2) interactions between normal genes and the environment (often without a family history); 3) congenital defects in certain genes (often with a family history and inherited to the next generation). Diseases caused by such congenital gene defects do not result in the onset of disease in all members of the family. The onset of a genetic defect and the type of onset are determined by the function of the defective gene and how that gene is inherited. Based on the incidence in the family line, clinicians can speculate and analyze the mode of inheritance, as well as combine clinical manifestations and clinical experience to speculate which disease may be present, and perform purposeful genetic testing in tens of millions of genes. Mutations in most genes can lead to changes in the quantity or quality of functional proteins (which play important biological roles, including participation in important metabolic reactions in the body) that can cause abnormal body functions and result in disease. Genetic testing is a technique that detects DNA through blood, other body fluids or cells, and can be used to diagnose disease and also for disease risk prediction. The leap forward in molecular biotechnology has amazingly increased the speed and accuracy of genetic testing, greatly reduced the cost, and provided great convenience for clinical genetic diagnosis (diagnosis of patients and prenatal diagnosis of pregnant women). It has been said that genes determine everything. Genetic sequencing can predict a person’s personality, looks, potential diseases, and control the destiny of each individual. There is some truth to these statements. Thus, some people advocate the theory that genes determine fate by creating a genetic data archive of each person after birth and arranging each person’s life according to his or her genetic data, including choosing food, medicine, work, and even finding a spouse, etc. However, there are some misconceptions and pitfalls hidden here. Genes are the basic units that control genetic traits and express the genetic information they carry by directing protein synthesis, thus controlling the performance of traits in individual organisms. However, this process of gene control of functional proteins is accomplished through complex, fine-grained regulation. While mutations in most genes have no significance for functionally important proteins (polymorphisms in mutations) or compensate for the effects caused by mutations through compensatory mechanisms, point mutations in certain genes can cause death or lifelong disability. Mutations in the same gene can cause different diseases, and different diseases can be caused by multiple different mutations, which is often referred to as genetic heterogeneity. Many patients often ask: “I’ve had my genes checked and the doctor told me there is nothing wrong with my genes, why do I continue to have them checked?” ”We don’t have any such patients in our family at all, and the doctor still says that the child has a genetic disease?” ”Our parents are normal, how can our child have a genetic disease?” ”The doctor said that the child’s genetic mutation has been found, so why do they still check the parents’ blood?” And so on. Genetic testing is a very serious matter and requires communication between the doctor and the patient to fully understand the purpose and significance of genetic testing and the accompanying risks. In particular, genetic testing for prenatal diagnosis may lead to doctor-patient disputes and lawsuits. I recommend that: 1. Patients must be clear about the purpose of genetic testing and the possible expected results before implementing genetic testing to avoid blind participation in genetic screening. 2. Doctors are responsible for their patients by explaining in detail the methods and purposes of genetic testing and the expected results. Genetic testing may not always lead to a clear conclusion. A doctor’s duty is to save lives and help the injured. Any injured person, whether friend or enemy, is a doctor’s service recipient. A doctor’s service is worthy of his or her conscience and the title of physician. Patients should find a doctor they trust. Since they believe in the doctor, they should communicate well with the doctor and accept the diagnosis and treatment according to the doctor’s will. Remember, the current level of doctors’ treatment and the limited medical conditions in hospitals. Do not look for a doctor or hospital to “settle the score” when medical risks arise.