Okay I have a ultrasound on December 18, 2013 saying 17weeks 2day pregnant. So that means the first week of pregnancy would be August 26, 2013 would be this first week of pregnancy. My brother had sex with his girlfriend on September 6, 2013. So that would means this person had a 2 week jump start on my brother. So I'm saying this person could have been at least 2 weeks maybe more pregnant.. He is doing a dna test because of the dates sounds fishy... Just need someone opinion or help wit the calculations cause maybe im not seeing it... Again he had sex with her September 6 2013, her pregnancy test said 3+weeks on September 26 2013 but she was 17weeks and 2 days Dec 18 2013... These are the real dates for a fact... Help our family out please anyone!