With Poser 4 and a model with enough morphs, you can replicate the physical features of a real person. Michael 2 and Victoria 2 are exmples of models with many morphs to shape the face in any way that you need. The stock Poser figures that comes with the program are more limited in this department. I have done models of two female friends using Victoria 2. It requires patience, but it's fun! To make it even more like the real person, you can apply a texture made from pictures of the persons face. For this, you will need PaintShop Pro, Photoshop or some similar picture editing software. This requires quite some skill and training. There is a tutorial out there on how to do this, maybe someone here can direct you to it.