Women do not see macho men as a sound bet for a long-term partnership, preferring those with more feminine features, a study suggests.
Men with masculine features like large noses and small eyes were seen as less warm, less faithful and worse parents than more feminine counterparts.
Some 400 British men and women made judgements after viewing photographs in which the features were subtly altered.
The study appears in the journal Personality and Individual Differences.
SPOT THE MACHO MAN
Lead author Dr Lynda Boothroyd of Durham University said: "This research shows a high amount of agreement between women about what they see, personality-wise, when asked to judge a book by its cover.
"They may well use that impression of someone to decide whether or not to engage with that person. That decision-making process all depends on what a woman is looking for in a relationship at that stage of her life."
Some 400 British men and women completed the web-based test which put a pair of pictures in front of them.
Participants were asked to judge the faces on the following categories: dominance, ambition, wealth, faithfulness, commitment, parenting and warmth. They did so by clicking on the point of a scale.
The differences were subtle but apparent to the trained eye. The feminine face had more curved eyebrows, an arched forehead and slightly higher cheekbones. He also wore a hint of a smile, as women smile more often than men, the researchers said.
Both the women and the men who took part in the test judged the more feminine more favourably on faithfulness, commitment, parenting and warmth.
The masculine were seen as more dominant, but there was no difference between the two on ambition and wealth.
Dr George Fieldman, a principal lecturer in psychology at Buckingham Chilterns University College, said the findings in many ways "made sense".
"In a modern society physical strength is not a necessity but potentially a threat. A woman may choose a more feminine partner because it may reduce the chance of violence towards her and any offspring they produce.
"This research may have no immediate implications, but it does feed into our understanding of evolutionary psychology and why people make the choices they do."