These words refer to the uniting of both sexes in one individual, either in a biological or psychological sense. Bisexual is the most general of these, having the widest range of possible meaning. In a biological sense, it can refer to any living organism in which both male and female organs are present. For many forms of life, this is normal: bisexual flowers; bisexual angleworms. Thus, as a generic term, the word can group together all normally double-sexed plants and animals. In its reference to people, however, the word would never refer to those rare individuals who are abnormally born with both male and female organs. On the contrary, it refers to those people who, physiologically normal, are psychologically responsive to both sexes: that transitional phase when adolescents are bisexual in their sympathies and loyalties. Many psychologists view every individual as being normally bisexual in make-up, although only those men and women who have both homosexual and heterosexual relations can be called actively bisexual . The word is not likely to be used to describe someone whose appearance combines both male and female characteristics.

Hermaphroditic and androgynous are more clear-cut in their reference to biological description. Hermaphroditic refers most specifically as a zoological term to animals in which the organs of both sexes appear normally in each individual, whereas androgynous applies as a botanical term to such double-sexed plants: viewing the volvox either as a colony of cells or as a hermaphroditic organism; effecting the hybridizing of corn by the sexual polarization of a normally androgynous species. Among such sexually polarized species as man, of course, a hermaphroditic individual may rarely occur as a biological abnormality, but the word would be strictly reserved for those cases in which both male and female sexual organs are anatomically present. Sometimes hermaphroditic is used less technically to refer to general appearance that partakes of both sexes. In this case, the word carries a tone of hyperbolic disapproval or amusement: The hair styles of young people grow more and more hermaphroditic . Androgynous has a more formal ring even in its strict biological use, and can sound abstruse or curious when it applies more generally; here, it is not so likely to be confused with reference to biological structure: cultures in which sexual role-playing is relatively androgynous outside such biological functions as child-bearing.

Epicene has no relevance to biological classification whatever, referring strictly to someone who in appearance or attitudes unites qualities of both sexes: a large, puffy face with soft features that were strikingly epicene in appearance. The word usually carries a disapproving or at least negative tone. Unlike bisexual , epicene may not refer to activity at all and may in fact suggest someone who appears sexless or is marked by no strong characteristics of either sex. In a culture that places a high value on manliness, epicene can often refer to effeminacy in men or even to neurasthenic male qualities: cultural stereotypes of the virile warrior and the epicene intellectual.