My friends and I were bored enough to try out this activity.
Picture a teenage boy in your mind.
From this picture, remove any accessories (glasses, piercings, etc.), moustache or beard, then replace the hairstyle with that of a stereotypical teenage girl.
Are you possibly convinced if someone tells you that, this picture was originally of a teenage girl?
I tried it by picturing a few boys who are my friends, but still, I was never convinced because I feel that there's something inherent about the facial features of these boys that made them appear boyish rather than girlish.
If this is not some psychological effect caused by my acquaintance with the boys I pictured (as I know them well so I cannot accept the mapping of their faces to the opposite gender), then are there really biological factors, genes in sex chromosomes in particular, that result in differences in the development of facial features between males and females?
Apparently, "facial hair" isn't an acceptable answer...