Combining Multiple Sprites

I'm working on a game that has different customizable body parts for an entity. Each body part is associated with an attribute and a sprite. When breeding two entities together, a child will be generated, randomly, of the attributes of its parents. I'm trying to find a way to combine all these sprites and create a unified sprite for the child.

How should I go about that? Is there other way to have the appearances of the child, resembling its stats, which are randomly assigned?