I had sex for the first time with my girlfriend 12/21/06 while she was on her period. She got her period 1 day before (12/20/06). She tells me the last time she had sex was 12/1/06 with a different partner. My questions are 1. If the baby is mine, how many weeks should the baby be? She tells me 4 weeks and some days but it doesn't add up to me. My other question is could the baby be mine?

Since it is often hard to date an exact day and time,

In general you can tell if the baby is yours by a dna test after the baby is born. And I would say if you had unprotected sex with someone who had just a few weekd before had sex with someone else maybe unprotected, you could be exposeed to 100's of possible things, you need some serious medical tests.

1. If she was on her period the day before you had sex, then the likely hood is that the baby is yours, but you still need to get a dna test to make shure, since she seems a little promisquious. And 2. the baby should be about 4 weeks along by now.

If you had sex with the girl you are talking about, then yes you could be the father. If when you had sex with her you wore a condom then yes you could be the father, if you did not have an orgasm while you were in her then yes you could be the father. If you had an orgasm outside of her and then entered her later there is a very good chance you could be the father.

Since she had her period after she had sex with the different man, then most likely it wasn't him that got her pregnant(provided she has been faithful to you since her period.) I am guessing you had sex after she got off her period as well?? (as it is very possible to get pregnant while on your period, but is less likely. But it does happen now on occasion) If you really care for this girl, and you think she feels the same way and is faithful, then just assume that this baby is yours, and don't question it. Once baby is born, you can have a paternity test done if it is still bothering you. Good luck

Conception timing is not a precise science. DNA testing is. Wait for the baby to be born and have a test done. No sense in speculating before then.

Dude just get a dna test. When a girl is on her period there's not much of a chance of her getting pregnant but there's still the chance. If I were you I would get a dna test. It won't hurt and you'll know for sure