The tendency for men to not be able to integrate the "dualisms" of women. Though EACH and EVERY female IS in fact fully capable of BOTH, it appears man's greatest challenge is to resolve them both in the same woman, thus these two aspects of the female must be relegated into two very separate and distinct categories--one or the other, black or white, Madonna or Whore. It's a shame men can't just accept that both are available to them in the same woman.
She's a Madonna, and a Whore. This introduces a complex dilemma. Madonna-Whore Complex.