Any discussion of sex and gender flows fairly naturally onward to the question of sexual orientation, because those aspects of identity are a major part of how we formulate the entire notion of orientation in the first place. Though it is not the case, as people used to assume (or at least mandate), that one’s sex dictates who one wants to sleep with.
In many of these essays I try to start with historical underpinnings, but in this case I think it’s more fruitful to begin with modern terminology. Nowadays the most dominant element in how we discuss people’s sexual practices is the question of who they’re attracted to — and specifically, the sex thereof. Heterosexuals are attracted to the opposite sex; homosexuals are attracted to the same sex. Bisexuals are attracted to both, but since that term reinforces the idea of a binary, some prefer the term “pansexual” to indicate their attraction encompassing all.
This is not, of course, the same thing as actually being attracted to all people. We all have our preferences, and may find individuals more or less appealing based on factors other than their sex or gender. Nor do these terms form clearly-defined boxes; Alfred Kinsey’s ground-breaking research in the ’40s and ’50s placed people on a seven-point spectrum from exclusively heterosexual to exclusively homosexual desire, and acknowledged that individuals may shift along that scale at different point in their lives.
That’s only one of two angles from which we discuss sexuality, though. The other major one, added more recently, is frequency of sexual desire, with “asexual” (sometimes abbreviated to “ace”) being the absence or near-absence of such impulses. Related terms, such as “gray asexuality,” describe the spectrum of those who experience some desire, but not often, and “demisexual” has come into limited usage for those who need a strong emotional connection to a person before they experience desire. (And though my focus here is on sexuality, I should note in passing that many of these terms have romantic analogues, such as bi-romantic or aromantic/aro.)
So that’s how we discuss these matters nowadays. When we look at the past, though, the scene very rapidly changes.
Not in the sense that people didn’t engage in these kinds of behaviors. They absolutely did, sometimes in very public and well-recorded ways. But just as our current concept of “gender” is a recent one, so is “sexual orientation,” in the sense of being an identity assigned to or claimed by individuals. The earliest scheme for this that I know of dates to the 1860s; the term “homosexual” wasn’t coined until 1869 and didn’t become popular until 1886, with “heterosexual” coined at the same time but not gaining real traction until the 20th century. Though, of course, there were plenty of other terms used for people who engaged in same-sex relations — most of them derogatory.
Kinsey’s scale, mentioned above, didn’t measure people’s identities; it measured their experiences, whether desired or actual. As I mentioned in the essay on non-binary gender, some third genders are built around the idea of homosexual orientation, packing those two together much as cis gender used to pack in the assumption of heterosexuality. When looking at the past, it’s usually more fruitful to look at this from the standpoint of behavior — of what people did — rather than how they may have defined themselves internally (which in most cases we’ll never know).
Take the view of homosexuality in seventeenth-century England. The closest thing to “homosexual,” in the identity sense, was “sodomite.” But a sodomite wasn’t just a man who had sex with other men; he was also a violation of many other societal norms, associated with witchcraft, devil worship, popery (seen as the nearly same thing in that time and place), and other things that threaten the dissolution of the world. As a result, the writings of the period give you the sense that certain men would have hastened to assure you that they were not sodomites. They were just men who had perhaps engaged in some vices not spoken of in polite company. There was no way to speak of people for whom that was simply their preference — though in places you can see contemporary writers floundering around for a word they didn’t have.
It’s also important to bear in mind that although the identity of the object of desire is one of the mainstays of how we think about sexuality, that isn’t the only way it’s been conceptualized. In ancient Rome, male citizens often had sex not only with their wives and female mistresses, but with their male slaves, male prostitutes, and so forth. Were they all bisexual?
Framing the question that way misses the point. Men of that class were defined in part by the right to protect their bodies against physical assault — which included corporal punishment. In sexual matters, this meant that citizen male sexuality was defined by the active role: they were the ones who did the penetrating, regardless of their partner. The scandalous behavior for them was not having sex with men, but being penetrated by someone else. Allowing that to happen grouped them with women and non-citizen men, whose sexuality was expected to follow a passive model. (It’s telling that apparently Roman men could barely even conceive of female homosexuality, and when they imagined it, one of the participants had a dildo or a really large clitoris.) They still didn’t speak of this in terms of “orientation” like we do, but by looking at what types of sex were expected vs. forbidden, we can see where they drew the lines.
Which means there’s room for different conceptions entirely. We’re getting that right now, with the addition of the asexuality-to-sexuality spectrum as kind of a cross-cut to the hetero-to-homosexuality spectrum. There’s also debate currently ongoing about whether polyamory should be thought of as a sexual orientation or not, essentially adding “number” to “object” and “frequency” as the factors we use to define this field. While that’s not a formally accepted definition at the moment (which would have implications as to whether polyamorous individuals are a protected class under certain laws), it’s certainly part of how some people describe their sexual identities. By contrast, there was a period of five years where the dating site OkCupid offered the option of “sapiosexual” for those attracted to intelligence — but they took it down in 2019 after a great deal of criticism and mockery.
In the end, the whole concept is a slippery one, with plenty of variation haring off in different directions. Only fitting, really, given that we’ve spent untold thousands of years conducting untold billions of experiments in our love for and attraction to our fellow human beings.