Appearance could be another indicator of the quality of a person's genes. Research suggests that there are certain things we all look for - even if we don't know it.

Perfect symmetry
It is thought that asymmetrical features are a sign of underlying genetic problems. Numerous studies in humans have shown that men in particular go for women with symmetrical faces. The preference in women for symmetry is not quite so pronounced. Women are also looking for a man's ability to offer food and protection. This might not be indicated in their genes, but in their rank and status, for example.

The hour-glass figure
Studies have shown that men prefer women with a waist to hip ratio of 0.7. You can calculate your own using this formula:

waist measurement ÷ hip measurement = ratio.

This seems to apply whatever the woman's overall weight. A group of researchers even compared this ratio with the average ratio of Miss America winners over the years. It was exactly the same. This ratio would seem to make sense as an indicator of a woman's reproductive health. When women age their waist tends to become less pronounced as they put on fat around the stomach. This coincides with them becoming less fertile.

Source:BBC