In order to produce diversity in virtual creatures to populate virtual worlds, different techniques exist. Some of these use blocks or sticks. In this morphological approach, blocks and sticks can be considered as organs, which means body parts able to perform different functions. Another approach, artificial embryogenesis, consists in developing organisms from a single cell. In this paper, we propose a bridge between these two approaches : a model that will create creatures with a particular morphology and which is organized in organs. The creature development will start from a single cell. In this paper, we propose a unique model able to produce organisms that perform a specific function and to produce organisms with a user-defined morphology.