Q: "Why do boys have a penis and girls don't?"
A: "In almost all animals, this is the big difference between males and females, and it has to do with the ability to make babies."
Kids catch on pretty early that one gender has extra flesh on the chest and the other more between the legs. But the minute we get the first body-related question, we clam up like a lawyered-up perp—for fear that they'll learn too much too soon. "While these questions aren't issues for children, they are for parents. But if they're wondering, just go right at it," says Alan Kazdin, Ph.D., professor of psychology and child psychiatry at Yale University. His suggestion for younger kids: Give the quick explanation above and then say that you'll tell them a little more when they get older. If you're brief and honest, that usually satisfies their curiosity.
Now, if the kids are older—around the double-digit range—you're going to have to tell them that when two people are in love, sometimes they express that love by inserting the penis into the vagina, both for pleasure and for producing a baby. This may also be a good time to give them a rundown of your family values surrounding sex—along with the facts about what can happen when you have it unsafely: specifically, catching a disease and becoming responsible for a baby of their own before they're ready.
Q: "What's the F-word?"
In the past few months, my boys have learned a new alphabet—the A-word, the S-word, even the P-word (at a Flyers game, as in "Get up, you [nice little kitty cat]!"). But for a long time, they thought the F-word was pronounced "foulk." When the question about an expletive does come up, Kazdin says, try not to yell or freak out (as in "Don't let me ever hear you say that again!"). If they've reached the age when they're likely to hear it and be curious about it (say, 7 or 8), just go ahead and tell them what the word means. Convey the point that you're happy they asked, and then explain that it's a word your family doesn't ever use and you will get in trouble if you do. "The reason those words have power is because adults don't talk to kids about this stuff," he says. "They have power because they cause a reaction. If a child knows them, then it's not a big deal—it takes all the energy out of it."