What are some advantages and disadvantages of prenatal diagnosis?

for example amniocentesis and Chorionic Villi sampling (CVS)

These two tests are done to check for genetic diseases that may not be compatible with life for the fetus. CVS can be done much earlier in the pregnancy than amniocentesis. They should not be done for the sole purpose of determining the sex of the baby. The advantage is if the fetus is affected, then the parents have the option of terminating the pregnancy or at least preparing to deal with the baby when it's born. the disadvantage is that these tests can cause the mother to have a miscarriage or develope an infection. I can't imagine anything worse than having the test, miscarrying and then finding out when the tests come back that the baby was a healthy one. Parent must consider the benefits and risks of such testing.