I think what Kelly really wanted to know was why her big sister acted so goofy when cute boys were around. This is a rather awkward conversation that everyone has experienced, either on the giving or receiving end if not both. I remember as a kid I did NOT want to hear about it, at least not from my dad. He knew this and understood the concept of a "captive audience" so he tended to bring up embarrassing subjects when I couldn't get away, like when we were driving down the highway. Actually, some families avoided the subject all together. My mom was seven when her baby sister was born. All she knew was that they were "expecting a baby" and little more than that was said. She and her siblings helped prepare the baby's stuff and so forth, but the mechanics of it weren't explained in the slightest. She had no idea why her mom was getting "fat," or why she suddenly became "thinner" when the baby came from... the hospital? I don't know. Basically, she had to wait until they talked about it in school several years later. I hope this is not too spicy for the TOS. If it is, I may just do spaceships from now on.