The sex of the fetus can be seen after 12 weeks of pregnancy, but non-medically indicated sex selection is prohibited in China, so it is not possible to see the sex of the fetus through formal means. After 12 weeks of pregnancy, the reproductive organs have developed and an ultrasound can reveal the sex of the fetus. In the middle of pregnancy, the sex of the fetus can be checked by taking the vein blood of the pregnant woman and isolating the DNA fragment of the fetus. The time for checking the sex of the fetus is somewhat related to the way of checking, and every method of checking has a certain degree of error. China’s law clearly stipulates that identification of the sex of the fetus for non-medical needs is prohibited, which means that doctors are not allowed to identify the sex of the fetus through any means when the fetus is healthy.