When I was researching this book in the early 1990s, I had to guess where I was likely to find published references to "heterosexual". But in the eleven years since 'Invention' was published, we've witnessed the spectacular advance of electronic database indexing, and the new availability of searchable texts of entire books, articles, and the full run of Major newspapers and periodicals, some going back to the nineteenth century and earlier. These now make possible many new, enlightening, and entertaining studies of what has been said in the mass media and academia about the "heterosexual", "heterosexuals", and "heterosexuality". Just try a search, be amused, be amazed, and let bloom a thousand term papers, theses, scholarly articles, and books!
(Jonathan Katz, The Invention of Heterosexuality: with a new preface, University of Chicago Press 2007 (1995), Preface 2006, http://books.google.de/books?id=S8BB1K361SUC&pg=PR7)

In the first chapter of this fascinating book, The Genealogy of a Sex Concept, Katz writes:

"A year earlier [1975], historian Carroll Smith-Rosenberg had published a path-breaking article on nineteenth-century American women's intense, eros-filled friendships, "The Female World of Love and Ritual". To understand those intimacies, she suggested, we need to go beyond the either/or, heterosexual/homosexual Division, and embrace the idea of a "continuum" of such relations. (...) With others, I was beginning to sense the distorting effect of employing the heterosexual/homosexual distinction in retrospective historical analysis. (...)

... If we have trouble imagining a world without heterosexuals or homosexuals, a historical perspective is useful. The term "homosexual" was only invented in 1869 [the year's now been moved back to '68]. The first use of "heterosexual" listed in the Oxford English Dictionary Supplement dates to 1901. [The most recent Oxford English Dictionary Supplement takes the date back to 1892, and "heterosexual" has also been traced to 1868.
The terms heterosexual and homosexual apparently came into common use only in the first quarter of this century; before that time, if words are clues to concepts, People did not conceive of a social universe polarized into heteros and homos."

By 1981, I had heard a young feminist historian and friend, Lisa Duggan, read a draft of a paper on women, American society in the 1920s, and "the social enforcement of heterosexuality". A few days later Duggans phrase set off in my head a flash of Illumination ... : "Heterosexuality wasn't only 'enforced', it was invented.' "

... and, in retrospective, again from the 2006 preface:

"My revised judgement about the role of words in the creation of "heterosexuality" and "homosexuality", is that those specific, historical phenomena did not exist, and could not have existed as such, before the words "heterosexual" and "homosexual" (and associated ideas) were available to describe them. (...) Actually, influenced and inspired by Karl Marx, I think that words, ideas, and ideals (like "heterosexual") are among our major means of production. Our struggle over the ownership, control, and shaping of those means is key to the future of heterosexuality, the other existing sexualities, and the new sexualities to come."