ultrasound blindness

Usually afflicting fathers-to-be and men and women who haven't been through pregnancy yet, this is a visual/brain problem that prevents a person from seeing in an ultrasound image where the baby is when it's perfectly obvious to the doctor and pregnant mother-to-be. Sometimes, but always, the pregnant woman will suffer from this affliction as well. You should worry if the doctor has it too.

Doctor: "Aaand there's our little guy!"
Mom: "Awww, he looks so cute! Doesn't he look beautiful, hon?"
Dad: "I-I guess so... Where is he again?"
Doctor: See? That's his hand with his 4 little fingers and thumb and you can also see his fingernails. And if you squint real hard you can see the individual atoms making up his penis."
Mom: "See honey? See his little peenee?"
Dad: "What...? I- don't... Wha...?"
Doctor to Mom: "He must be suffering from ultrasound blindness. Perfectly normal for fathers-to-be and village idiots. He's just not as awesome as you and I."
*both doctor and mom then laugh at dad's expense*