A study from Brown University has revealed that skin tone is associated with gender, with women on average having more green in their complexion, while men appear to be redder.
The group led by Professor Michael J. Tarr analyzed 100 images each of Caucasian males and females, controlled for lighting conditions, with subjects wearing no makeup. These were then processed on Matlab to create sexually ambiguous face images slightly distorted with visual noise that randomly included more red or green pixels.
Non-color blind subjects were then asked to identify the gender of the distorted images over repeated sessions (10 one hour sessions) and then the color content for each was analyzed.
On average the 'female' faces appeared greener, while the 'males' were redder, however this does not appear to be absolute and the use of color to identify objects is still controversial. Overall, this study demonstrates that observers use color to identify gender when other features are obscured.
Far more disturbing (though sadly not addressed in this paper) is the growing evidence to confirm long-held suspicions of the opposite sex: women are aliens and men are devilish!