There is no connection between a protruding belly button and the sex of the fetus. There are some ways to determine the sex of the fetus through external manifestations, such as observing whether the belly button is protruding or paying attention to the eating habits of the pregnant woman. These behaviors do not have any scientific basis, and to determine the sex of the fetus, you can use ultrasound or amniocentesis. China’s law stipulates that the identification of the sex of the fetus is illegal, so you can not know the sex of the fetus through various tests, and the behavior of the medical staff to tell the sex of the fetus will also violate the national law, pregnant women can not ask. Compared to the gender of the fetus is more important is the health of the fetus, it is recommended that the mother in the appropriate time to improve the obstetric examination, pay attention to healthy and nutritious diet, in order to help the healthy growth of the fetus, do not pay too much attention to the gender.