There is no scientific basis for the statement that there are more boys with right umbilical vein. The right umbilical vein, also known as the persistent right umbilical vein, is an anatomical variant. It usually means that the right umbilical vein, which is supposed to degenerate, does not degenerate and the left umbilical vein, which is not supposed to degenerate, does degenerate. And there is no scientific basis for the claim that the majority of right umbilical veins are in boys. If the right umbilical vein is purely persistent and there are no other areas of abnormality, the prognosis is good. In some fetuses, the right umbilical vein is combined with other anomalies, and if the other anomalies are severe, the prognosis of the fetus can be affected. The presence of right umbilical vein in the fetus should be checked for other malformations, and termination of pregnancy is necessary. In conclusion, the right umbilical vein of the fetus is not related to the sex of the fetus, and attention should be paid to whether the fetus is associated with other malformations.