This paper shows the latest results of our artificial embryogeny model [2]. In nature, cells are able to specialize their functions. This specialization allows the creation of cells groups that perform the same function, commonly named tissues. To perform a specific action, tissues are grouped in organs. The cell specialization happens at different stages in the organism?s development. The internals of this specialization is coded in the DNA molecule as a gene regulatory network and regulated during the growth with different proteins contained in the foetus neighborhood. In our project, we want to simulate this specialization using different levels of detail. This paper presents a model that forgets the complexity of chemistry and physics to focus on the complexity of cell?s mechanisms. Using this model, we want to generate artificial creature like Sims? ones [5].