Men's faces tend to be more reddish and women have more greenish skin, according to new research. Brown University scientists analyzed 200 images of Caucasian male and female faces under the same lighting conditions and with no makeup. First a computer program analyzed the amount of red and green pigment in the faces, then subjects were asked to decide on the gender of images of androgynous faces clouded by random shape and color patterns. Some women's faces are redder and some men's faces are greener, but in general the research showed that people use color when trying to identify gender, especially when the shape of a face is ambiguous. Lead researcher Michael J. Tarr described the subject's ability to determine the gender of the images as a "superstitious hallucination," like being in the shower and hearing the telephone ring when it hasn't. [EurekAlert]