Psychological, behavioral, and cultural varieties of discordance
In contrast to the small percentage of people with biological discordances of sex, a fairly large proportion of human beings may be "discordant" in one or more behavioral or psychological dimensions. The vast majority of these people who are discordant in some aspect of psyche or behavior do not have any detectable biological intersex condition. Human societies respond to, or accommodate, these behavioral and psychological discordances in many different ways, ranging from suppression and denial of difference to acknowledging various forms of "third sex."
It is interesting, and perhaps significant, that some societies identify youths with atypical behavioral characteristics and, instead of giving them corrective therapy or punishing them, socialize them in such a way that their individual characteristics let them provide a needed and/or useful function for the society in a recognized and respected role. (See, for example, shaman, medicine man, tong-ki.)
See the article Pictogram for an example of a pictogram of a man and a woman, to indicate the respective toilets. It shows the man with broader shoulders (sex dimorphism) and the woman in clothing that is in the western world rarely worn by men, a dress (which functions as a gender signal). (Presumably these "male human" and "female human" pictograms are not used in countries where men wear dress-like clothing.) In most societies, it is considered improper for a person of one sex to misrepresent himself or herself as a member of the opposite sex by donning inappropriate clothing (thereby practicing transvestism or, colloquially, cross-dressing). Such behavior receives severe social and/or legal sanctions in some cultures.
See also berdache, hijra, xanith and transgender.)
Such complex situations have led some scientists to argue that the two sexes are cultural constructions. Some people have sought to define their sexuality and sexual identity in non-polar terms in the belief that the simple division of all humans into "males" and "females" does not fit their individual conditions. A proponent of this movement away from polar oppositions, 
