Agnostic, 
Her Wikipedia entry states: "babyfaced individuals are seen as physically weaker, more submissive and less competent". 
 
Besides, she is a Social Psychologist who's interest is how people think others see them. Wide faces are not the same as round faces. Think NFL. The reason people see babyfaced individuals as wimps is because they usually are wimps, whether they try to overcompensate for it or not. Just another visual cue. But there must be some reproductive advantage. Maybe they hung around the campsites while the more masculine men went hunting. That would have given them a chance to impregnate the women in camp. A quick search of Nobel Prize winners doesn't yield too many babyfaced/moonfaced people.

I'm just guessing, though I'd be willing to bet a small amount of money that Agnostic not only has a face as smooth as a babies bottom but also a marble shaped head. The reason why people associate baby faces with a lack of testosterone is because that's what they see around them as they go about their life. All of the baby faced people I've ever known were pretty much what you'd call a pansy. Round head or not.