what's a virgin?

During yesterday's Gospel reading, Noah was reading along when he came across an apparently unfamiliar word: virgin. So he politely whispered to me, "Mom, what's a virgin?" I quietly told him that we would have to talk about it later - how do you get into that discussion with a 5 year old while the rest of the Gospel is read? He and I both forgot the question until this evening when something in a conversation with Michael triggered it in my memory. I told Noah to ask his dad the question he asked me in church and with a little reminder, he did indeed ask, "Dad, what's a virgin?" Michael's response: "A virgin is someone who hasn't had sex." To which, at the exact same time, Noah and I both said, "Dad, what is sex?" Michael and I started laughing and Noah laughed because we were laughing and then said, "Like INSECTS, get it? Insects!" Ahh, the joys of parenting...