Like good art, beauty in the human form is not purely an arbitrary matter of personal taste–well, think about it, personal taste is hardly arbitrary, either. It can be described by the number Phi—which makes a fascinating read, by the way, if you follow that link. Your art and design will be the better for understanding this.
But back to human beauty. IF you are a Poser user, you have the ability to morph faces on your human figures, whichever ones you use. Want to make something ugly or good looking intentionally? We have the lowdown, thanks to Jim Farris (again).