When you go to find out the gender of your baby, they will tell you that it's not 100% accurate but let's be honest, we trust those flimsy pieces of paper to be telling us the truth.
So when the ultrasound technician told parents Kyle and Danielle Williams that they were having a girl, they went out and got all the pink things. So imagine their surprise when the doctor congratulated them on their beautiful baby boy!
It's not a new story, this has happened to so many couples and once the Williamses had gotten over their shock they decided to upload their family's reactions to the news to YouTube. My favourite one is the grandmother who makes the discovery when changing baby's nappy in hospital.