My daughter had several ultrasounds the first 6 months due to high risk with diabetes. Everytime, the tech would say it looked like a boy, or was fairly certain it's a boy, and when asked point blank, even noted it on one of the photos as MALE. Then in her 7th month she was refering to her baby as "he" and a new tech asked her why she was under the assumption the baby was a boy, and she explained. He then pointed to a very nice view of 2 legs, 2 little bottom cheeks and NOTHING between... It was a girl after all. What's really cute is, my daughter had already started the baby book in blues, browns, and greens with trucks and numbers and had the name all stamped and done in scrap book fashion like you wouldn't believe! It was adorable, but then on about the 12th page it says, "so we went to the dr again and to our surprise" and you turn the page, and it glows in pink and lavendar with lace and flowers and says "YOU'RE A GIRL!" And sure enough, she's a girl, and so adorable we can't imagine her as a boy. So, yes it can be wrong. But it turns out just right in the end.