According to researchers at the University of St Andrews, Scotland, women with high levels of the sex hormone oestrogen have prettier faces.

The findings are not as trite as they may initially appear and make evolutionary sense, as in most animal species males are attracted to the most fertile females.

During puberty oestrogen levels can have a huge impact on appearance by affecting bone growth and skin texture.

But often make-up masks this effect, allowing less attractive women to compensate for their lack of natural mating cues.

The team of psychologists at the University’s Perception Lab photographed 59 young women’s faces aged between 18 and 25 and analysed their sex hormone levels.

They then asked 30 volunteers, 15 male and 15 female, to rate the faces according to attractiveness, and it seems that both male and female volunteers rated the faces of the women with the highest hormone levels as the most attractive.

The faces rated the most attractive tended to have classically feminine features, such as larger eyes and lips and smaller noses and jaws.

However, when the women in the photographs were wearing make-up, no relationship between attractiveness and oestrogen was found, which has led the researchers to deduce that, while make-up improves facial appearance, it may also be masking cues normally seen in the face.

Therefore it appears that many women are employing a deceptive strategy by fooling the male visual system with make-up.

Miriam Law Smith, the lead researcher, says that women are effectively advertising their general fertility with their faces, and make-up can improve appearance across the board, but it will obviously help people who are less attractive more.

Eye make-up can make the eyes seem bigger and foundation can make the skin look smoother.

According to Dr Tony Little, a lecturer in the School of Biological Sciences at the University of Liverpool, the study is interesting and makes sense.

He says there are clear benefits to choosing particular types of female faces, and oestrogen is related to fertility.

Dr Little says he and his colleagues have found in their studies female attractiveness also fluctuated throughout the   menstrual cycle, peaking at a woman’s most fertile days.