Um before 18 weeks all genitals look the same so you would never be able to tell....
This is actually not true - you can determine gender prior to 18 weeks (they start to look different around 13 weeks or so). I found out my son was a boy at 14w 1d and there was no doubting it. Confirmed again at 17 weeks, 26 weeks, 31 weeks, lol. Etc. But 8 weeks? Not a chance. Sorry, but boys and girls both have "wing wangs" at that gestational age.