For many years, scientists believed that when lovers gaze at each other they are merely using facial clues - large eyes, small nose, large lips and so on - to check that their prospective mate has high "fitness" and can efficiently pass their genes to the next generation. Scientists who showed men the faces of young women found that women with higher levels of estrogen were rated as more attractive, healthy and feminine-looking than those with lower levels.
The research suggests a deep-rooted evolutionary link between beauty and reproductive fitness which has helped men to identify mates who will bear them large numbers of offspring.
The female sex hormone oestrogen was thought to be the mediator of beauty, which advertises health and fecundity. Now researchers at the University of St Andrews have shown for the first time that women with higher levels of oestrogen do indeed have more attractive faces.
The study, published today in the Proceedings of the Royal Society: Biological Sciences is the first to demonstrate that women's facial appearance is linked to their well-being because oestrogen impacts on women's reproductive health and fertility. Telegraph.co.uk. Psychologist Miriam Law Smith, who led the team of psychologists at St Andrew University's Perception Lab, said: "The relationships between oestrogen and appearance in natural images of faces found here are important because they are the first evidence for a link between facial femininity and oestrogen that has previously been assumed in facial attractiveness research, Scotsman reports.
"People have speculated for years that women with more attractive and healthy looking faces have higher oestrogen," said Miriam Law Smith.
Hormones exert most effect on the face during puberty, she said. The principal male sex hormone testosterone causes the jaw and eyebrow ridges to become more prominent and facial hair to grow, making boys' faces grow more than girls'.
The female sex hormone oestrogen prevents the growth of facial bone, reduces the size of the nose and chin, and leads to large eyes, increased thickness of lips and fat deposition in the cheek area, along with hips and buttocks, features that announce that a woman is fertile.
At first sight, the discovery that beauty is more than skin deep suggests that oestrogen injections could boost the attractiveness of a developing female face. However, the way the body would react to an artificial boost is unknown and there would be a downside, as underlined by the risks of hormone replacement therapy. Moreover, today's study shows the effects of hormones are easily masked by the application of make-up. A.M.