This is from a posting on the Freakonomics blog. This is just way too funny.

My favorite story concerns my son Nicholas:

Relatively early on in the pregnancy we had an ultrasound. The
technician said that although it was very early, he thought he could
predict whether it would be a boy or a girl, if we wanted to know. We
said, “Yes, absolutely we want to know.” He told us he thought it would
be a boy, although he couldn’t be certain.

“How sure are you?” I asked

“I’m about 50-50,” he replied.

Don’t take that technician to Vegas. He’ll having you picking numbers at roulette, and playing the horn in craps.