Anthropological classification of homosexualityWhile homosexuality has been present in almost all societies since the dawn of time, the forms in which it has been found vary widely. Anthropologists who have studied homosexuality distinguish three main types of homosexuality: gender-structured, age-structured and egalitarian.
In gender-structured homosexuality, each partner plays a different gender role. Examples of gender-structured homosexuality include the butch/femme distinction found among some modern Western lesbians (although butch/femme is in decline).
In age-structured homosexuality, the partners are of different ages. Examples of this include pederasty among the ancient Greek elite (sex between adolescents and older men was socially respectable, but sex between grown men much less so) and traditional Melanesian insemination rituals (where adolescents would fellate older males as part of the process of initiation). (Some might see some modern pedophilia as being an example of age-structured homosexuality, but it is different in that it is not socially acceptable, unlike the Greek or Melanesian practices.)
Both gender-structured and age-structured homosexuality frequently involve one partner adopting a 'passive' and the other an 'active' role. Among men, being the passive partner often means being the receptacle of semen, i.e. performing fellatio and being the receptive partner in anal sex. This may mean an emphasis on the sexual pleasure of the active partner, although dogmatism about this is unwise. (In gender-structured female homosexuality in Thailand, active partners (toms) emphasise the sexual pleasure of the passive partner (dee), and often refuse to allow their dee to pleasure them.)
In egalitarian homosexuality, the partners are of equal age (or age is of no relevance in the partnership structure) and both play the same socially-accepted sex role as heterosexuals of their own sex. Egalitarian homosexuality is increasingly dominating the Western world, replacing age- and gender-structured homosexuality within it; and from the West egalitarian homosexuality is spreading to non-Western societies as well, although they maintain a much higher incidence of non-egalitarian than the West does.
Some anthropologists have argued for the existence of a fourth type of homosexuality, class-structured homosexuality; but many scholars believe that this has no independent existence from the other three types.