My neighbour was told on I think 8 different occasions that she was having a boy. She had a girl. This was about 10 years ago so I guess the machines are better these days but I still would've thought they would've got it right somewhere along the line. She only found out it was a girl at the birth.

I would never have gone out buying blue clothes for my bub if I hadn't known for sure that it was indeed a he. I knew this as we'd had an amnio. Even so my sonographer told me of an incident where an amnio report said one sex and the ultrasound clearly showed the opposite sex. Turned out the person typing the amnio report and done a typo - the actual results showed it was the sex that matched the scan. Luckily the parents of the bub didn't want to know the sex so there was no disappointment involved.