It's no secret that a crying woman is typically not a turn-on to the average guy, but now there's a scientific study to prove it. According to new research published in the journal Science last week, there is a unique chemical component in the tears women cry when sad, and it leads men to be less sexually aroused. Here, a brief guide to the study:

What did the study find?
Men who sniffed women's emotional tears were less aroused and less interested in women than when they sniffed a neutral saline solution. This suggests there's a unique chemical in emotional tears that can influence the behavior of others. "Chemical signaling is a form of language," says Dr. Noam Sobel, one of the study's researchers and a professor of neurobiology at Israel's Weizmann Institute. "Basically what we've found is the chemo-signaling word for 'no' — or at least 'not now.'"

How was the research conducted?
Six women who "were really good" at crying their eyes out formed a "bank of criers" for the study. They watched scenes from emotional films such as My Sister's Keeper, Terms of Endearment, and When a Man Loves a Woman to produce a flow of fresh tears. Researchers dribbled the tears on pads to be sniffed by 24 men in their late 20s. On some days, the men unknowingly sniffed a saline solution instead, for comparison. While they sniffed, they were shown pictures of women, or in other instances, a trailer for a sports movie. The researchers tracked the men's sexual arousal by their testosterone levels, brain imaging, skin responses, and the men's own description of their state.

Why might our bodies be programmed in this manner?
"Why women's tears would send a message of 'not tonight, dear' is puzzling," says Pam Belluck in The New York Times. It could be to help reduce the risk of rape or be an evolutionary means of lessening men's aggression toward women under duress. And there is evidence that women cry a lot during menstruation, which from a biological standpoint "is not a very effective time to have sex," says Dr. Noam Sobel, one of the study's researchers and a professor of neurobiology at Israel's Weizmann Institute. "So reducing sexual arousal in your mate at that time is really convenient."

Why weren't the effects of men's tears studied?
The researchers originally set out to study both men and women's tears, but only one man responded to their ad seeking those who could cry prolifically.

Sources: The New York Times, Reuters, Time, ABC News