Where do Babies come from?

All of a sudden our nearly 5 year old triplets are very interested in knowing where babies come from.  Audrey recently read an article that said that now is a good age to tell the kids how babies are made.  Darcy, who is most interested in figuring out this conundrum asked again at dinner tonight. Using her "article" as her resource, Audrey told the kids, "Mommy has eggs, like a chicken, and Daddy has sperm, and when the egg and sperm get together, the baby begins to grow".  Darcy frowned at Audrey and said, "no no no Mommy, I want to know where people babies come from".