If DNA is the blueprint for making proteins which are used to make the cells, then how does DNA "know" which proteins to make for the certain type of cell (bone, skin, muscle, etc.) it is creating? Is this started by the reproductive organs of the parent telling embryonic stem cells what to do in the beginning, and then those just making that same type of cell over and over again? Or is this something that the embryo's own DNA tells them to do with no outside influence?