If we feel "embarassing" to tell our children, this would be the better way to "explain" in this cyber world...
"Daddy? How did I come into this world?"
"Well, my child, some day I'll have to tell you any way."
"So why not today? Please!"
"OK, but listen carefully. Mom and Dad met each other in a cyber cafe. In the restrooms of that cyber cafe, dad connected to mom. Mom at that time made some downloads from dad's memory stick. When dad finished uploading we discovered we used no firewall. Since it was too late to cancel or delete, nine months later we ended up with a virus."