Only a DNA test would beale to tell you what one is the father. They can do a DNA test when you are still pregnant. Here is some info

Paternity Testing While Pregnant

It is not generally done, but here is some advice and input:


Prenatal DNA Paternity Testing

A DNA paternity test can be performed accurately before a child is born through amniocentesis and chorionic villus sampling.

Chorionic Villus Sampling (CVS)
Chorionic Villus Sampling is usually performed at very early stages of pregnancy, generally around the 8th to 13th week of pregnancy. During the CVS procedure, a catheter is inserted through the cervix and a small sample is taken from the outside of the gestational sack by gentle suction. This sampling procedure allows the obstetrician to obtain a small amount of fetal chorionic villi (trophoblastic tissue) which is used for the paternity test. Paternity tests conducted using CVS samples are just as accurate as tests which are performed after the child is born.

Amniocentesis
Amniocentesis is generally performed at later stages of pregnancy. During an amniocenteses procedure, a small amount of amniotic fluid (10ml) is withdrawn transabdominally by your obstetrician. Amniotic fluid is also an excellent sample for paternity testing; paternity tests which are performed using amniotic fluid are just as accurate as tests conducted after the child is born.



It's possible, kind of. Something called Chorionic Villus Sampling can be used to take a sample from the womb and test for genetic abnormalities like Downs' Syndrome. I guess this can be used for genetic paternity testing, but that's a very big expensive deal.
You can do a paternity test after an amniocentesis, but it would not be worth the risk or the expense.
I don't think so, but one can be taken the day the baby is born. And it will only take a few days to a week to get the results.
Some places will but they have to stick a long needle through your belly to the baby. But most don't like getting that done cause they may not know where they stick the baby to get blood.
Yes, you are able to have a procedure called an amniocentesis. A sample of amniotic fluid is taken with the use of a needle and an ultrasound scan. DNA is tested from the amniotic fluid. You will also need DNA samples from the alleged father eg buccal swab from the mouth. There is minimal risk when having this procedure. You may also have blood cord samples taken when a child is born and this procedure is totally safe.
The procedure is not risk free. The baby could be killed as a direct result of this procedure. Approximately one in every two hundred pregnancies in which this test is performed is lost as a result.

P.s Good Luck and keep us updated.