Hi, Kimmy,
I just answered you on the other thread where you posted, and here is what I said.
Your best info is not that from your app (the assumptions on which apps are based come from the average woman's average cycle) and not from the measurement from your last period (because women can ovulate almost any time in their menstrual month), but your first ultrasound is golden. You had the ultrasound on just about the perfect day to be spot-on when figuring the date of conception, and it counts back (from your October 4 due date) to January 11 with a margin for error of only about 1 day. You're right that everything points to guy #2.
In your shoes, I'd assume all through the pregnancy that guy #2 is the dad. Then I'd do a DNA test after the baby is born, not so much because the data is questionable but just to put the whole issue to rest forever.
Congratulations on your pregnancy!
Annie
The only sure way to know for sure is to do a DNA test. It is likely that guy 2 is the bio father, but since you have doubts, you owe it to yourself, both men and the baby to find out for sure who the father is.
The miscarriage prior should have no effect on conception date after 2 regular cycles.
Were you trying to get pregnant? Just curious because of the recent miscarriage and concerns over your conception date/paternity. Were you not using birth control? I honestly am not trying to be rude or nosey, it just makes me curious if you planned to get pregnant?