Recently released results from Dr Tony Little and his team, suggest that males with more feminine features are more widely attractive to women. Women who consider themselves highly attractive however, are more likely to go for classically masculine faces.
Dr Little is interested in identifying the features of attractiveness and explaining why we might have evolved to recognise and seek-out beauty.
The link might be explained by the fact that some physically attractive features are linked to levels of hormones (such as testosterone) that are present during development. These are also known to have an influence on fertility and coupling behaviour.
The researchers based their findings on data gathered from staff and students at the University of Liverpool, but have an online lab where you can take part in similar experiments.
Link to the research team’s online lab.
Link to BBC News story on the research findings.
Mind Hacks 
Penton-Voak (personality in face researcher) talked about this – apparently, though, things get interesting when you switch from static to dynamic input: using video the masculine faces are often rated better, and there’s an idea that macho faces code for potential threat, which an image does nothing to dispell (being a fixed slice of time), but if you see the person acting non-agressively then this is discounted. I can’t remember the precise details though.