• The sexual regions constitute a particularly vulnerable spot, and remain so even in man, and the need for their protection which thus exists conflicts with the prominent display required for sexual allurement. This end is far more effectively attained, with greater advantage and less disadvantage, by concentrating the chief ensigns of sexual attractiveness on the upper and more conspicuous parts of the body. This method is well-nigh universal among animals as well as in man.

    Havelock Ellis (1905). “Studies in the Psychology of Sex: Sexual selection in man: I. Touch. II. Smell. III. Hearing. IV. Vision”