Just been for my 20 week scan. I didn't want to know the sex and told the sonographer this as with my 2 x DS's, I also didn't want to know but thought they 'flashed' me during the scan. Of course, this might have been a coincidence and I didn't see bits but they were boys anyway. I didnt see anything with my DD who was my first but it was all new the first time and I was probably a bit overwhelmed.
She told me when she was going into that area and me and DH looked away. However, later on in the scan I thought I saw bits. It wasn't a through the legs shot, it was looking at baby from the front (baby was looking right at us.
Can you even see bits from that angle as all the images from google that show boys bits do it by showing it looking through the legs.
I'm not bothered if its a boy or a girl this time, I just don't like to think the surprise has gone. DH didn't see anything but he's not the most observant.