We all know that sexual attraction in heterosexual intercourse is important, as it subconsciously links the subconscious to the ability to leave offspring. Generally, for men attraction to a woman is related to waist-to-waist ratio and body mass. 

To go further, they tend to see more of the chest, hips and waist compared to other parts of the body because in these areas they get more information whether they feel physical traction or not. 

In addition to the one we mentioned, another component that was very much related to physical attraction is the color of the clothes that women choose. According to studies, red is one of the most attractive colors for men because it is associated with love and passion. 

Color also has a big impact on other psychological factors, including humor and decision making. For example, bright colors tend to be associated with positive emotions, and dark colors with negative emotions, which may also explain how color can affect our perception of physical attraction.

If it is clear to women what men value in them as attractive, it is also understandable that they want to be able to appreciate how attractive another woman is to make comparisons with herself. This is firstly to assess the chances in selecting the partner and secondly to have "under control" what kind of competitor can pose a threat to the relationship.

The 'red color effect' theory, which states that men rate women who wear red as more attractive because of a connection to passion and sexual ability, was also found to apply to women judging other women. .

Researchers have concluded that less attractive a woman resembled green or gray dress, this is probably due to personal color preferences. In general, red is preferred by all as it is associated with being dominant, while gray and green are associated with lukewarm energy. 

Source: Psychology Today