Nothing in our lives brings us joy like small children. But they are also a challenge. Maybe that is why there are so many jokes about raising children.

"We child-proofed our home," said one comedian, "but they are still getting in."

"If you have a lot of tension and you get a headache," says another, "do what it says on the aspirin bottle: "˜TAKE TWO ASPIRIN' and "KEEP AWAY FROM CHILDREN."

Some of you will identify with Rita Rudner's line: "I think about having children, because time is running out. I want to have children while my parents are still young enough to take care of them."

One mother listened as her seven-year-old son explained what he'd learned in school one day. He asked his four-year-old brother, "Did you know you're made up of atoms?"

The younger boy looked thoughtful…