Butch and femme are terms often used in the lesbian and gay subcultures to describe approximate equivalents of traditional masculine and feminine gender roles, respectively, of members of the same sex within a relationship, or to describe individuals.
However, homosexual relationships do not easily fit into butch and a femme stereotypes. For example, a lipstick lesbian is a feminine woman who is attracted to other feminine women. Among homosexuals the practices of 'femme on femme' and 'butch on butch' sex preferences are sometimes repressed by cultural mores. Many gay men will only date other masculine men, though others prefer femme men.
The site Straightacting.com is an example of a humorous site where homosexual men and women may measure and discuss their butch-ness or femme-ness. Interestingly, this site seems to stereotype lesbians as always wanting a butch/femme relationship and gay men as wanting a butch/butch or femme/femme relationship.