Tears could contain chemical signals that act as a biological communication system. Israeli scientists found that a woman’s tears decreased male testosterone levels and the desire for sex, compared to a placebo (fake tears composed of saline). They were not sure if male tears had the same effect because they had trouble recruiting enough male criers. Also, only fresh tears were effective for biological communications. Frozen tears did not have the same effect.
In another study using MRI, areas of the brain associated with sexual arousal were less active when men could sniff a woman’s tears. It appears that female tears are like sexual kryptonite. (The New York Times, January 7, 2011)