Yes, but
it is usually not a good idea. One way is to test amniotic
cells for the child's specimen. The mother's doctor can
perform amniocentesis, to extract amniotic fluid. The
fluid is then sent to PTC for testing.
There
is significant cost to perform the amniocentesis. More
importantly, the amniocentesis presents medical risks
to the mother and the child. You should discuss those
risks with your doctor. Because of those risks, most doctors
prefer not to perform an amniocentesis unless there are
medical reasons requiring the procedure. If the mother
is going to have amniocentesis for medical reasons, then
there is no reason not to perform the paternity test.
Otherwise, it is better to wait until the baby is born
to perform the paternity test.
Another method that can be used is Chorionic Villus Sampling (CVS).This method of testing has substantial risk (including birth defects) and should never be used for the sole purpose of paternity testing. If CVS is going to be performed for medical reasons then it can also be used for paternity testing.