Women with higher levels of testosterone are more attracted to masculine looking men like celebrity beefcakes Russell Crowe and Daniel Craig.
And men with raised levels of the same hormone are more attracted to feminine looking faces like those of Lost star Evangeline Lilly and the actress Natalie Portman.
These are the findings of the University of Aberdeen's Face Research Laboratory which reveal that changes in testosterone levels affect the extent to which men and women are attracted to different types of faces.
It has been assumed that people are attracted to other people because they are drawn to particular types.
But Drs Ben Jones, Lisa DeBruine and Lisa Welling have shown that testosterone levels appear to be the key.
Theirs is the first study to reveal the role the hormone plays in making certain women attractive to certain men.
The researchers asked male and female volunteers to complete short face preference tests in which they were shown pairs of masculine and feminine faces. Participants were asked to choose which face from each pair was more attractive.
Men and women completed four different test sessions that were each a week apart. In each session, volunteers also provided a saliva sample which was used to measure testosterone levels.
Dr Jones, a Psychology lecturer, said: "People preferred different types of face in the session where their testosterone level was highest than in the session where it was lowest.
"When men's testosterone levels were high, they were more attracted to feminine women. When women's testosterone levels were high, they were more attracted to masculine men.
"Since masculine men and feminine women are thought to produce the healthiest children and sex drive is higher when testosterone levels are also high, these findings suggest that men and women in hormonal states where their interest in sex is highest, show stronger attraction to high quality – or healthy – mates."
Dr Welling added: "We tend to think that attraction is relatively stable over time. However, our research shows that attraction is affected by fluctuations in testosterone levels."
Drs Jones and DeBruine will be talking about their research at Innovate with Aberdeen, The Frontiers of Excellence which is taking place at the University of Aberdeen on Thursday, September 18, and is open to all.
Source: University of Aberdeen