According to MSN.com, the gender of a fetus can be determined through diagnostic procedures such as ultrasound, amniocentesis and chorionic villus sampling. Amniocentesis and chorionic villus sampling are invasive procedures, while ultrasound is not.
The American Pregnancy Association explains that in an ultrasound procedure, high-frequency sound waves are used to scan the abdomen and pelvic cavity of the pregnant women in order to create an image of the placenta and the baby. According to MSN.com, the gender of the fetus can be determined during the fourth or fifth month of pregnancy.
FamilyDoctor.org states that amniocentesis is conducted by inserting a needle through the mother's abdomen in order to obtain an amniotic fluid sample from her uterus. This fluid sample is then evaluated in a laboratory. This procedure does not harm the baby; the mother might experience cramps during or after the test.
On the other hand, FamilyDoctor.com explains that chorionic villus sampling is performed by getting a sample of the mother's placenta with the use of a catheter or a needle. Either a catheter is inserted through the vagina, or a needle is inserted into the abdomen to obtain the sample. The sample of the placenta is then analyzed to determine the gender of the fetus.
According to MSN.com, although amniocentesis and chorionic villus sampling can determine the gender of the fetus, they are commonly performed in order to detect possible health problems, such as Down syndrome or cystic fibrosis.