* Amniocentesis: This test is performed in the second trimester, anywhere from the 14th-20th weeks of pregnancy. During this procedure, the doctor uses ultrasound to guide a thin needle into your uterus, through your abdomen. The needle draws out a small amount of amniotic fluid, which is tested. Risks include a small chance of harming the baby and miscarriage. Other side effects may include cramping, leaking amniotic fluid, and vaginal bleeding. A doctor's consent is needed to do this procedure for paternity testing.

* Chorionic Villus Sampling (CVS): This test consists of a thin needle or tube which a doctor inserts from the vagina, through the cervix, guided by an ultrasound, to obtain chorionic villi. Chorionic villi are little finger like pieces of tissue attached to the wall of the uterus. The chorionic villi and the fetus come from the same fertilized egg, and have the same genetic makeup. This testing can be done earlier in pregnancy from the 10th-13th weeks. A doctor's consent is needed to do this procedure for paternity testing.

And it issues an important warning:

Prenatal DNA testing done in conjunction with other prenatal testing involves some risk associated with how the testing is conducted, whether amniocentesis or CVS. These tests are often discouraged for the sole reason of seeking paternity because of the increased miscarriage risk.

For those desiring more practical information about how to go ahead with arranging DNA testing during pregnancy, there are several commercial organizations that offer more detail.

The GeneTree DNA Testing Laboratory has several pages on pre-natal DNA testing. The DNA Diagnostics Center also has information. Both companies offer to help find appropriate doctors.