In a similar fashion to myths, stereotyping originates from an infinitesimal bit of truth. Sexuality and appearance have their antecedents in the need for a man and a woman to find each other attractive so as to want to engage in sexual activities, thus ensuring the continuation of the human race. All species on this planet that require both a male member of the species and a female member of the species to combine genetic material in order to procreate have a form of courtship...no matter how short. In much of the animal world it's the male who puts on the colorful show to attract a female. Keeping up appearance ensures the continuation of the species. Once progeny arrives, one of the mated couple cares for the young while the other hunts for food.
Human behavior revolving around finding someone sexually attractive is a form of this animalistic behavior. Stereotyping has come out of the criteria set up by individual cultures and societies stemming from the ancient need to find an attractive, willing mate, procreate then have someone to care for the home, hearth and children while the other spouse brings home the bacon, and protects the home, hearth and children.
When it comes to stereotyping and what men and women find attractive in and/or about each other men have been indoctrinated into the concept of feeling threatened by a woman who's not soft, curvy and docile while a woman feel sexually attracted to and safe, with a muscular, confident, healthy man.
The media and advertising play a major role in the promotion of stereotyping and keeping up appearance. Before any social function but most importantly a date, everyone agonizes over whether they will be able to give that good first impression. That first impression is all about keeping up appearance, wearing clothing appropriately stylish, color coordinated, standing tall, walking properly, stomach in chest out and the list goes on. Stereotyping physical appearance while perhaps regrettable is a pervasive mindset and as such must be paid attention to if one wants to be a viable member of society.
Social psychologists have found that we're affected by the physical beauty of others-albeit a matter of personal preference without even seeing them. They also tell us that good looking people are not only seen as beautiful but are perceived to have a more pleasant personality and be more competent that those less well endowed. They are deemed more intelligent as well. Individuals very often reflect in their manner and mental state the way that they are treated by others. If treated as if beautiful, etc. there is a higher likelihood of feeling that way and therefore acting that way and being treated that way. The opposite is of course true as well. Those that fall prey to an unwillingness in keeping up appearance may find themselves being treated with less respect, will feel bad about themselves and will behave accordingly. The stereotyping of appearances becomes a self-fulfilling prophecy.
Stereotyping mode of dress and body care has led to misconceptions and mistakes in judging a person's sexual proclivities. While in past centuries men pampered and preened as much as women, in the past few decades stereotyping caused many men to feel they would be judged negatively if they put too much emphasis on their outward physical appearance. Stereotypically it has been felt that men who gave attention to their hair, clothing etc. were gay no self-respecting heterosexual would display such behavior.
However, times have changed and many heterosexual men no longer feel it necessary to adhere to the old ways of thinking and now take care of themselves as totally as any woman. The term used to describe these gentlemen is "metrosexual".