A normal baby with amniocentesis still has the possibility of a genetic mutation. The best time for amniocentesis is between the 16th and 21st weeks to analyze the number of chromosomes and whether the structure is abnormal. It is the most commonly used method of fetal karyotyping, but it only guarantees that the fetus is healthy during the period prior to the test, and because the fetus is constantly growing, there is still a possibility of genetic mutation, but the possibility is relatively small. In general, the fetus is most likely to have genetic mutations before 12 weeks, but it does not mean that genetic mutations will not occur after that, for example, there were cases in which the fetal diameters were consistent with the gestational week at 21 weeks, and the amniotic fluid volume was normal, but the test was performed at 31 weeks to detect the genetic mutations and skeletal developmental abnormalities, etc. Therefore, it is not absolutely clear that amniocentesis is healthy during the period before the test. Therefore, it is not absolutely clear that a normal amniocentesis baby will not have a genetic mutation.