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?"

To which the man matter-of-factly replies, "Those are called condoms, son. Men use them to have safe sex."

"Oh I see.", replied the boy pensively. "Yes, I've heard of that in health class at school." He looks over the display and picks up a package of 3 and ask, "Why are there 3 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 6-pack 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..."