There are no prominent features in the ultrasound of pregnant girls, and the ultrasound will not clearly express the gender characteristics of the fetus. However, when the fetus reaches 3-4 months of age, the external genitalia of the fetus begin to develop completely, and the doctor can determine the sex of the fetus by observing the shape of the external genitalia through ultrasound examination. But now the state explicitly prohibits fetal sex identification, except for suspected sex chromosome genetic disorders, you can determine the sex of the fetus through ultrasound or amniocentesis DNA test, in addition to all non-medical needs to identify the sex of the fetus, are illegal. Moreover, male and female are the same, as long as the baby develops normally. It is recommended that mothers have regular maternity checks and pay attention to rest. During pregnancy, it is necessary to strengthen nutrition and ensure a balanced diet, you can consume more food rich in high-quality protein and vitamins, and eat more fresh fruits and vegetables, so as to ensure the healthy growth and development of the fetus. At the same time, pregnant women are affected by estrogen and progesterone, and their moods fluctuate, sometimes being moody and unpredictable. The emotional changes of pregnant women have a direct impact on the health of the fetus, so pregnant women should adjust their mindset appropriately and not be overly concerned about whether they are having a boy or a girl, and keep a relaxed and happy mood to actively welcome the birth of a new life.