Masculinity..

 

 A team of human behavioralists at the University of Queensland, in Australia, working with a colleague from the University of Stirling, in the U.K., has found via experimentation that people tend to be more attracted to potential partners that look like them. 

An old adage suggests that "opposites attract," but it might be referring more to personality than looks.

Face similarity between couples played a role in how attractive they found each other—the more alike they looked, the more attractive they found the other person. 

Those of the same ethnicity more attractive than people of other ethnicities. 
And the researchers found that the volunteers tended to rate the other person as more understanding and more trustworthy the more they looked like them.

Women tended to rate men as more attractive based on how masculine they looked and women as less attractive the more masculine they looked.

Oops there it is. Just a thought.