With DD1 I was told boy @ 20 weeks luckily I had to go and have the another scan @ 24 weeks & then the same woman said she was a girl.
She showed me the hamburger so It was very obvious, I reminded her that I was in with her just 4 weeks prior and she had told me boy & she just said that she must have mistaken the cord for a penis...
With this baby it was very obvious he was not a girl, as his scrotum and penis were clearly visible....