Why 12?

A man and his young son are in the drugstore when the son comes across the condoms and asks his father what they are. The dad replies, "Well son, those are condoms and they're for protection when you're having sex."

The son then picks up one of the packs and asks why it has three in it. The dad replies, "Those are for high school boys. One for Friday, one for Saturday, and one for Sunday."

The son then picks up one with six condoms asks, "Why six?"

The dad replies, "Well son, those are for college men. Two for Friday, two for Saturday and two for Sunday."

The son then notices the 12 pack of condoms and asks the same question.

The dad replies, "Son, those are for married men. One for January, one for February, one for March...."