What came first, the Tadpole or the Egg?

This is the conversation I over heard this morning, while ironing the clothes. Between Dasher and Emmah....................
D: "Emmah, the egg came first."
E: " no, a frog is a tadpole before he is frog."
D: "but, it is an egg, before it is a tadpole, then a frog."
E: "NO!"
D: "Mom, what came first, the egg or the tadpole?"
Mom: "first it is an egg, then it hatches, and become a tadpole and then grows up to be a frog."
D: "Emmah, if you don't believe me, go ask mom, she just told me."
E: " I don't care, I think it was tadpole."
Mom: "Emmah, first it is an egg. In fact we start as eggs, called zygotes, then we become a baby."
D: "Yeah, and the mommies lay their eggs, and that's how we get here."
Mom: "Well, not exactly."
E: "Oh, that's why mommies tummies are shaped like eggs when there is a baby inside."
Dad: "You guys don't have it all right, but if that makes sense then that is how we will keep it for now."

I had to document this because it is so fascinating to see children's minds work. They used their problem solving skills, worked together, and figured out why mommies tummies are shaped like eggs!!!! :)