Why don't you believe your Ultrasound Tech!?

For the ladies that post pics of their ultrasounds with the description being something like "they told me it was a boy/girl but I don't believe them." Why don't you believe them? Why do you get on here asking us?? Your not a trained ultrasound tech and we aren't either for crying out loud!! If your that uneasy about it just ask for another ultrasound because your uneducated opinion as well as any that we might have won't give you a definite answer. I swear that makes no sense at all. I'm not saying they're right 100% of the time but geesh people get it together!! And don't say it just "for fun" because you really do want to know the sex of your baby, so look for a way to get a second opinion if you're truly concerned!!