"Condoms" joke

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 boys 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 asks, "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........"