There is reason to doubt the veracity of our current taxonomy of sexualities: a person (we think) is by nature homosexual, heterosexual, bisexual, or asexual. Admittedly, this system has an intuitive appeal: there are two genders (basically); one may be attracted to one, the other, both, or neither. There are no other possibilities. This satisfying quality of logical completeness is misleading, however.
The first and most important piece of evidence against our system is that people never thought of sexuality in this way prior to the 19th century. For ancient Greeks and Romans (and nearly all other non-Jewish cultures of the ancient world, according to Dennis Prager), homoerotic expressions were generally considered normal and carried no moral stigma, and they were not thought to express a different type of sexuality. Plato’s Phaedrus, for example, which deals with the nature of romantic love, takes as its central examples what we would call “homosexual” relationships. But the same-gendered-ness of the lovers does not seem significant enough to the interlocutors to even warrant comment. Romantic love was a sort of divine madness (according to Socrates) that one person contracted towards another. He evidently felt that gender played no essential role in the process. Similarly, in other dialogues of Plato, the character Socrates sometimes refers to the beautiful [male] youths and the lovely women who inspire sexual impulses in his interlocutors, lumping the two types of attraction together and presuming that his interlocutors experienced both. Per our current taxonomy, we might say that the Greeks were apparently predominantly bisexual. But they did not think of themselves that way. There were simply sexual, and their sexuality could be expressed with persons of either gender. Significantly, even in this society, where there was no moral stigma attached to “homosexuality,” marriage was exclusively male/female. Why? Presumably because only male/female unions produced children, and therefore only such unions involved a strong social interest in the stability provided by marriage.
Nor did the medieval world divide sexuality as we do. Christianity was the dominant moral and intellectual system, so there was a strong moral stigma attached to behavior we now call “homosexual.” They called it “sodomy,” and it was generally both a crime and a sin—but it did not make the perpetrator “homosexual.”
Thus, both the classic and medieval worlds are united in declining to divide sexuality into categories based on the gender(s) towards which sexual attraction was oriented.
The classic and medieval worlds had no concept of “homosexuality,” but is there really any difference between saying, as they did, that a person is simply sexual (and that sexuality may be directed towards either, both, or neither genders), and saying, as we do, that a person may be homosexual, heterosexual, bisexual, or asexual? Yes. It goes from being a characteristic of one’s behavior to being a characteristic of one’s nature—from a part of one’s history to a part of one’s identity. One “is” homosexual—note the to-be verb.
This shift from behavior to identity is, in my opinion, wholly bad.
I believe that the ancient and medieval system is more natural and healthy, while ours is more artificial and problematic.
If I am right, it goes without saying that Justice Kennedy was flatly wrong when he announced in Obergefell that sexual orientation is an “immutable characteristic.”
If I am right, Denis Prager (a Jewish commentator whose essay on Jewish sexual doctrine and the rise of Western civilization is quite possibly the most interesting writing I’ve ever read on sexual topics) is correct when he says,
Human sexuality, especially male sexuality, is polymorphous, or utterly wild (far more so than animal sexuality). Men have had sex with women and with men; with little girls and young boys; with a single partner and in large groups; with total strangers and immediate family members; and with a variety of domesticated animals. They have achieved orgasm with inanimate objects such as leather, shoes, and other pieces of clothing, through urinating and defecating on each other . . . ; by dressing in women’s garments; by watching other human beings being tortured; by fondling children of either sex; by listening to a woman’s disembodied voice (e.g., “phone sex”); and, of course, by looking at pictures of bodies or parts of bodies. There is little, animate or inanimate, that has not excited some men to orgasm.
If I am right, the potentiality for sexual interest in either gender is natural in nearly all people in some degree, and particular actualizations of that potentiality (whether I fall in love with X, for example) can to some debatable degree be effectively encouraged or discouraged by the individuals themselves, the social groups to which they belong, and their society as a whole.
 Foucault (himself leading a “gay” lifestyle) gives us a persuasive explanation about how the current taxonomy arose. No doubt there are other theories as well, and I would like to learn about them if anyone can point me to a good source. As to Foucault’s explanation, you can read it in his History of Sexuality or cheat (like me) and just read the Wikipedia page. It is interesting but not especially pertinent here.
 Readers should not assume from this example that I believe that falling in love is reducible to sexuality. I don’t. But sexuality is generally a part of it.