One study claimed that women who have infectious diseases during their pregnancy, are more likely to give birth to asymmetrical babies. They also claim that these asymmetrical babies will grow up to suffer more heart disease than their more symmetrical cousins.

Here’s another example involving humans. In the animal kingdom, it’s the secondary sexual characteristics that are most different from one side of the body to the other. One of the secondary sexual characteristics for women are the breasts. Women’s breasts can differ in circumference, from one side to the other, by as much as 30%!

One study showed a relationship between the number of children that a woman had, and the symmetry of her breasts. According to this study, women with more evenly-sized breasts had lots of children, while women with differently-sized breasts had fewer children.

In another study, people with asymmetrical teeth tended to have more nasty micro-organisms in their mouths. And people suffering from schizophrenia tend to have a bigger difference between the fingerprints of their left and right hands, than non-schizophrenics.

Symmetry counts even in the plant kingdom. Bees prefer symmetrical flowers. In general, symmetrical flowers produce more nectar than asymmetrical flowers. (We know this happens, but we don’t yet understand why.) In one study, bees were twice as likely to visit a symmetrical flower, as compared to an asymmetrical flower. When a researcher used his scissors to turn a symmetrical flower into an asymmetrical flower, it suddenly became unattractive to bees, even though it had just as much nectar as before! [Source]