A man walks into a drug store with his 8-year-old son. They happen to walk by the condom display, and the boy asks, "What are these, Dad?"
The man matter-of-factly replies, "Those are called condoms, son. Men use them to have safe sex."
"Oh I see," replied the boys pensively. "Yes, I've heard of that in health class at school."
He looks over the display and picks up a package of three and asks, "Why are there three in this package."
The dad replies, "Those are for high-school boys. One for Friday, one for Saturday, and one for Sunday."
"Cool!" says the boy. He notices a pack of six and asks "Then who are these for?"
"Those are for college men," the dad answers, "Two for Friday, two for Saturday, and two for Sunday."
"WOW!" exclaimed the boy. "Then who uses these?" he asks, picking up a 12-pack.
With a sigh, the dad replied, "Those are for married men. One for January, one for February, one for March."