I have just been severely put off an otherwise interesting book on medieval gender (Simon Gaunt, Gender and Genre in Medieval French Literature), by its sloppy use of terminology and lack of historical perspective. He starts quoting Gayle Rubin and Eve Kosofsky Sedgwick on compulsory heterosexuality and then comes out with the ridiculous claim: homophobia, like misogyny is an inevitable product of patriarchy. Just how culture-bound can you get? Ancient Greece and Rome were undeniably patriarchal societies, but you can hardly call them homophobic.
And what on earth does compulsory heterosexuality mean anyhow? It may work as a concept for modern Western society, but it certainly does not for many premodern societies. Gayle Rubin (in her classic article The Traffic in Women), trying to locate obligatory homosexuality in prehistory, claims the incest taboo presupposes a prior, less articulate taboo on homosexuality. But again this theory doesnt cope with societies (classical or other) that have incest taboos, but no taboos on homosexuality. You dont have to assume that incest taboos are for eugenic reasons to see that incestuous relations which are potentially fertile are likely to be more socially disruptive than intrinsically non-fertile relations (since they are more likely to be discovered and have more consequences) and therefore that it is those ones which get mentioned. (As an interesting aside, Judaism developed prohibitions on sleeping with ones grandmother later than with ones granddaughter).
The term compulsory homosexuality seems to me to be unhelpful in several ways. Firstly, what you can often see in the modern world is not compulsory but presumed heterosexuality. It is assumed that people will be straight and systems/patterns have been developed which follow these assumptions. For example, if I am talking to a woman Ive just met and she says my partner works at X, I would probably say: What does he do? This is an assumption on my part of the sex of the partner (although one that is likely to be accurate nine times out of ten). If I was wrong, I would expect to apologise and then carry on with the conversation as normal.
Such kinds of heteronormativity may be very irritating for gays, but I dont think can accurately be called compulsory heterosexuality. As an analogy, theres a difference between assuming all people are right-handed and forcing them to be. Compulsory heterosexuality seems to me to require more social pressure. But even here, there seems to be a tendency to conflate together several different demands made historically by society on individuals:
1) compulsory procreation – that individuals must reproduce
this was common in ancient Mediterranean cultures (e.g. Greek/Roman), but is entirely compatible with any number of homosexual relationships combined with marriage
2) compulsory non-homosexuality – that individuals must:
a) not desire their own sex
b) not engage in same-sex sexual acts
these, I would say, were the most common medieval demands. Note that these both allow a positive valuation of asexuality/celibacy.
3) compulsory heterosexuality- that individuals must:
a) desire the opposite sex
b) engage in opposite-sex sexual acts
these are different from 2) because they mean that asexuality and celibacy are no longer valued. Instead lack of opposite-sex desire/activity is taken as a sign of same-sex desire/activity.
By this definition compulsory heterosexuality is obviously commonplace today, especially in certain macho environments. The interesting question is about the history of this and I think its quite complex. There are medieval examples of such attitudes (for example where celibate priests are presumed to be sodomites or when claustration is said to be essential to preserve the chastity of monks/nuns) but I dont think its the dominant discourse until the end of the Middle Ages or even later. I think for men the Reformation did pretty much endorse the unnaturalness of male celibacy and that more or less remained the normal view. For women, Im less sure. I think asexuality in women retained at least some of its positive value for far longer. I suspect, for example, that it was only in late Victorian period (or maybe even later), that a pair of spinsters living together would come to seem suspicious.
I dont follow the view of some scholars like James Schultz, who think that the term heterosexuality isnt useful in medieval studies. I think there is presumed heterosexuality inherent in most medieval texts, unlike in classical ones. (Once you can no longer have debates about whether the love of boys or girls is better, you know presumed heterosexuality has come in). But I dont think compulsory heterosexuality is a useful term to be using, unless you think rather more carefully (and historically) than most scholars of gender seem to do about the topic.