I am a neurologist and in my medical practice, I often encounter anxious and depressed patients who are young and talented, but can feel anxious about a common category of problems in society, which is the doubt of paternity, which poses a great health risk, so I searched a lot of literature to try to find an early and effective and safe method that can help such patients. Before 12 weeks of gestation is called early pregnancy and paternity determination during early pregnancy is a problem that has faced medicine for many years. In the past, paternity testing generally had to wait until the birth of the fetus or abortion, induction of labor before termination of pregnancy is necessary to obtain fetal genetic information, there are also in the middle of pregnancy using amniotic fluid cells for paternity testing, but at that time the fetus is already formed, and if the induction of labor, will be more harmful to the pregnant woman, so I I checked a lot of literature, and came up with a more feasible method called biopsy of the chorionic villi. Paternity test. The principle is commonly known as the use of villi tissue, extracting a sufficient amount of dna, and the father dna as a comparison, and then compare the two groups of genetic molding. The advantage of this method is that the early pregnancy rocket or the technique of taking villi, not only can the time of paternity test be advanced to 6 to 8 weeks, but also can clarify the paternity without disturbing the pregnancy, and overcome some defects, if the paternity test result is clear, in the case of timely termination of pregnancy, the damage to all aspects is minimal. Then the next issue that we are most concerned about is the chorionic villus sampling clinical technique is safe or not, generally we use the blind method, the blind method is to use a 1 to 2 mm diameter plastic tube, through the cervix into the uterine cavity, busy west can get the chorionic tissue, this method almost no major impact on pregnant women, and on the literature statistics to see the birth of babies from height, weight and intelligence, and normal babies consistent There are no corresponding effects. When it comes to side effects, there may be a very small miscarriage rate, generally less than 5%, and a small amount of vaginal bleeding may occur in about 10% of people, none of which is directly caused by this technique. Overall, this technique is still very safe. The third core issue is the final result of this technique, how accurate is it? The accuracy can be comparable to the sensitivity of parentage DNA matching. It can reach more than 95%. The factors that may affect the accuracy of the test, I have done a summary of the literature, the general theme can be the following aspects. First, contamination of maternal tissue can affect the test results, second, fetal dna lesions formed by mutated germ cells involved in fertilization are also genetic mutations that occur because of problems with the father’s sperm, and third, incorrect results due to mutations in the chromaffin cells. How to overcome the error? The broad approach is to choose DNA fingerprinting test plus PCR typing to improve the accuracy when doing this test. The core obstacle of this test is the amount of chorionic villi taken, as long as the amount is sufficient to extract DNA, the result will definitely be obtained. So the trouble with this test is that the specimen may be taken several times. To summarize, if you want to do a paternity test, and if you want to know who the child is at an early stage, then this method is very feasible: the biopsy of the chorionic villi. The time to do this can be done from the time of calculating menopause, after six weeks. The accuracy rate is relatively high, and the impact on the child is relatively small, and if the abortion is carried out, the harm to the pregnant woman is also relatively small.