Mommy, where do babies come from?

Okay, so how many of you with young children prepare yourself to be asked "the question" when they are 4 years old? Well, I know that I didn't even think about the possibility that this question could be coming up yet. But yesterday it did! We were in the car on our way to the mall and Halie asked, "Mommy, how do you get babies in your belly?" I gave her the usual response that I've used when we've talked about it before and told her that Heavenly Father puts the baby in there. Yesterday she wasn't accepting that as an answer. She just kept saying, "Yeah, but how?" So I went a step further and added the "when daddy and mommy love each other" phrase at the beginning of my first explanation. She still wasn't satisfied. "Yeah, but how?" So, as I was giggling like a nervous child and trying to figure out what to say to her, I came up with the thought that I should tell her that mommy has a tiny egg in my belly and Heavenly Father makes the egg turn into a baby. So that's what I did. She seemed to accept that, or at least she thought about it for a few seconds, but then she said, "So an egg comes out of your belly and the baby hatches?" That started a whole new conversation! A word of advice...don't use my explanation!
So after this conversation, I thought to ask her why she asked me a question. I thought maybe some punk at her preschool had put ideas in her head. This was not the case. She explained that she just wants mommy to have another baby in my belly and wasn't sure how it would get in there. Then she started discussing what we would name her baby sister. (And in case you're wondering, NO, I am absolutely not pregnant! Apparently my daughter is just a planner!)