It can be possible that she knew about her pregnancy after one week of her conception date. The conception date is usually 14 days before your periods. If her period was 3rd June then she might conceived in May according to her cycle( it may vary). If yes then it is possible that she knew about her pregnancy on Jan 8. The ultrasound can tell you many things. She had got pregnant not in Sept but in May or June.
She would become pregnant beginning of Sep. Approx ( end of Aug a poss. ) as it is a nine month process. Without more detail of her LP it is impossible to be more precise. But a baby from conception to birth normally takes 266 days but a dr. Will normally ask you when your last period started and he will count forward 280 days from the first day of your last p, which is exactly the same as counting the 266 days from day 14 of your period. It is easier to do the maths. Zuhael,s May or June answer is clearly wrong as this give a birth in Feb/.March. KTlil too is clearly wrong ,. Yes a scan can show the gender of the baby and many other things.
Maybe in October since her due date is in June
I think Zuhail misread the question and Tklilbrat is just incorrect. She is due in June and found out the sex of the baby in January. If this girl is due June 5 then she is 25 weeks pg right now and would have been about 19 weeks pg when she found out the sex of the baby. That's definitely not too early to find out the sex. Most people have their big gender ultrasound between about 18-22 weeks. And since she is due on June 5th going backwards yes she would have gotten pregnant in early September. Figuring due dates is not an exact science especially if she wasn't charting her cycles. But in all likelihood she went to the doctor who asked what the first day of her last period was and they used that. In this case that would have been in late August. The average woman ovulates about two weeks later though it can be as early as about 10 days after their period started. September 5th would have been a bit early for her to ovulate but if her body was preparing to ovulate there would have been fertile quality mucus inside of her which can keep sperm alive for as long as five days afterwards! So if your question is can a baby be due on June 3rd from sex that occurred on September 5th then the answer is yes. Any time more than 6 days or so after your period begins is considered the fertile time in a woman's cycle.