Women with larger chins are more likely to be unfaithful to their partners, according to a new study.
The researchers have found that prominent jawline can be a telltale sign that a woman is likely to cheat.
Larger chins are often a result of high level of the male growth hormone testosterone, present in all women in various amounts.
The hormone also increases sexual assertiveness in a woman, a tendency more commonly attributed to males.
During the study, the researchers looked at young women from four universities across the US and Canada, and questioned them on their sexual histories and fantasies.
They found that men subconsciously move away from large chinned women following the evolutionary desire to have a partner who will produce children for only one man.
For instance, actress Meg Ryan, 47, who has a prominent jawline, famously cheated on her husband Dennis Quaid with her co-star Russell Crowe.
"The findings are important in demonstrating that perceptions of women as desirable and trustworthy long-term mates can be reliably gleaned by men from viewing only the women's facial features," the Telegraph quoted the authors as saying.
"Results suggest that information about women's sexual unrestrictedness, which is related to their risk of infidelity, can potentially be conveyed by the masculinity of women's faces," they added.
Dr. Lorne Campbell, a psychologist from Western Ontario University, who took part in the project, said: "It is difficult to conceal physical features, such as facial characteristics, that are partly governed by testosterone and reliably correlate with one's sexual history and attitudes.
"The research is the first to our knowledge to suggest that a more masculine facial appearance in women might convey their sexual unrestrictedness and perhaps their long-term mate quality," Campbell added.