There may not be a specific attraction-insecurity gene but insecurity itself has to be genetic. It is a mild form of fear, and without fear we'd do all kinds of dangerous stuff over and over and die before we were 10 years old.
I think insecurity can take many forms. A person may become angry, or embarrassed, or arrogant or a number of other conditions. I think the point at which the ball leaves the hand, so to speak, in the fat pants quetion is where the insecurity manifests itself in vanity.
From the posts here it seems there definitely is much concern over females appearance, likely based in insecurity. Not one woman here yet has claimed that asking such a quetion is proper. I think the reason for this is a moral/ethical issue.
Is fear genetic or learned? Emotional responses can be attributed to activity in the brain and that would be genetic. The conditions that evoke these responses appear to be learned behaviors formed from society. I think insecurity is the social manifestation of the genetic capability to experience fear.