My wife just had her ultrasound a couple days ago (about 26 weeks in). The session lasted about 10 minutes. At the start of the session, the doctor "hummed" and said that the baby's position still wasn't very revealing.
Then right before they end, he focused on a circular part and said, "it's a boy". However, he did not point out any penis, and neither my wife nor I could see the "turtle's head" popping out anywhere. For some reason as well, the doc wouldn't give us the ultrasound shot of that... just the standard profile pic. So... I'm wondering... was he correct in the assessment of a boy or was he jumping the gun a little bit and didn't want to give us the snap shot as a "just in case." We're going in for another ultrasound in 2.5 weeks (same doctor), so we'll get to see again then, but would be kinda nice to know if it sounds legit or still semi-inconclusive.
Its hard to tell....sometimes the position of the baby makes it impossible to tell. Sometimes they are so sure and then completely wrong about the gender even after several sessions.... Just have them take another look when you go in next.