Men looking for a quick fling prefer women with more feminine facial features, a new study has found.

The study investigated whether considering partners for long-term or short-term relationships would affect men's preference for different women's faces.

One of the experiments was conducted on-line with 393 heterosexual men. From this group 207 stated they had a current partner.

Participants were shown 10 paired images of pictures of women and in each pair of composite images one had been further transformed to possess masculine traits and the other feminine traits.

The men were asked to rate which of each pair they found most attractive indicating the most attractive for short term relationships and long term relationships.

The results showed that men in relationships were more likely to find women with feminine faces most attractive when they were looking for a short-term relationship.

"It's interesting that these findings are comparable to previous research that indicates women's preference for masculine male faces are higher if they were judging for short-term relationships.

"Our findings point to a similar preference in men. When they already have a partner, men find more feminine women more attractive for short-term relationships," researchers said.

Researchers said there are several possible explanations, perhaps some men are inclined to take a long-term partner whilst still attempting to cheat with other, more feminine, women.

Or maybe once a long-term partner is secured, the potential cost of being discovered may increase a man's choosiness regarding short-term partners relative to unpartnered men, they said.

"In another part of the study we also showed that men who think themselves attractive have stronger preferences for femininity than those who think themselves less attractive.

"Again, this effect appears similar to an effect seen in women, whereby attractive women are choosier in their preferences for men. Across the two studies attractive men were found to be more discriminating in their preferences for a woman's facial femininity," the researchers wrote.

The findings by Anthony Little from the University of Stirling and Benedict Jones from the University of Glasgow appear in the British Journal of Psychology.