When I was in my early 20s, I used to babysit for my neighbor's two daughters. One evening as my boyfriend and I stood talking to their parents, 4-year-old Emily joined in with a conversation stopper.

"Do you have a penis?" she demanded of my boyfriend, who looked suddenly like a deer caught in the headlights. "Because," Emily continued, "my daddy has one. He says all boys have penises and all girls have vaginas."

"Uh, that's right," said my boyfriend weakly. And then all the grown-ups laughed with what could only be called relief. Later that evening, my boyfriend wondered whether it was right to teach little children such words. I shrugged. I had no idea.

Fifteen years later, with two little kids of my own, I'm still not sure I have the right answers. If you feel the way I do, take this quiz and find out what the experts suggest we say when our kids ask those embarrassing, conversation-stopping questions.