*'''Deoxyribonucleic acid tests:''' DNA tests look for overlaps in the child's unique genetic code with the genetic code from the purported father and the child's mother. Today's DNA tests deal with the probability of fatherhood in terms approaching absolute certainty; if a DNA test shows a man is probably the father, the odds that the test is wrong are about 0.0001%. Testing is performed on biological samples, most commonly blood samples. It is possible to have tests conducted based on mouth swabs.

*'''Chorionic villi sampling:''' This is a prenatal procedure that can be performed during the 10th to 13th week of pregnancy. It consists of a DNA test on a sample of the baby's placenta. It is an unpleasant procedure that must be conducted either through the mother's cervix or her abdominal wall.

The DNA of a child is a combination of the DNA of the child's mother and father. DNA tests compare the child's DNA to that of the father and mother, and provide a calculation of the odds that the man is the child's father. Because of the accuracy of DNA testing, a positive result will prove extremely convincing to a court. Unless you have a doctorate in genetics or convincing proof that a sample was tampered with, I don't recommend that you challenge the results of a DNA test. Save your money.