Scientists say when it comes to searching for a partner, the attraction of a potential mate is all about symmetry.
They say how symmetrical a person's body appears, the more attractive that person is to the opposite sex.
The idea that perfectly balanced features represent beauty is not a novel one, as far back as ancient Grecian times symmetry was regarded as an important ingredient in human judgments of beauty.
More recently beauties Greta Garbo and Marlena Dietrich were both considered to be remarkable for their perfectly symmetrical facial features and the same might be said of some of today's top models.
In new research from scientists at Brunel University in London, it is suggested that the same is true for body symmetry, and that symmetrical proportions could be signs of biological fitness.
Study leader Dr. William Brown says in animals with two sides that were designed by natural selection to be symmetrical, subtle departures from symmetry may reflect poor development or exposure to environmental or genetic stress.
He says in many species these departures are related to poor health, lower survival, and fewer offspring.
The researchers used a 3-D optical scanner, not dissimilar to ones used in the medical profession, to create detailed virtual models of the bodies of 77 adult human subjects which were measured for degrees of symmetry.
Brown and his colleagues then asked another group of 87 volunteers to rate the attractiveness of the bodies of the opposite sex based solely on visual appeal.
In order to remove any potential bias due to facial features or skin color, the heads of the virtual models were removed and the bodies were all tinted the same neutral shade.
Even though differences in left-right symmetry are as a rule almost undetectable to the naked eye, both men and women reported symmetrical bodies to be more attractive.
The researchers found that men with physical traits commonly associated with masculinity-such as being tall with broader shoulders and smaller hip-to-waist ratios tended to have more symmetrical bodies.
Women who were more symmetrical tended to have more typical feminine traits, such as larger hips, longer and more slender legs, and larger breasts.