Anatomy ultrasound and gender

So we had our anatomy ultrasound today. We told her we didn’t want to know the gender. Then a little later she said something like “oh look how cute he’s yawning.” Then she said just so you know I will use the words he or baby and it doesn’t mean anything one way or another. Now I’m kind of wondering if she slipped. Has this happened to anyone else and it wasn’t the slip up they had ?