Still, Freud’s explanation seemed to satisfy the majority of the public, who, continuing their obsession with standardising every aspect of life, happily accepted the new science of normal. Such attitudes found further scientific justification in the work of Alfred Kinsey, whose landmark 1948 study Sexual Behavior in the Human Male sought to rate the sexuality of men on a scale of zero (exclusively heterosexual) to six (exclusively homosexual). His findings led him to conclude that a large, if not majority, “portion of the male population has at least some homosexual experience between adolescence and old age”. While Kinsey’s study did open up the categories homo/hetero to allow for a certain sexual continuum, it also “emphatically reaffirmed the idea of a sexuality divided between” the two poles, as Katz notes.

The future of heterosexuality

And those categories have lingered to this day. “No one knows exactly why heterosexuals and homosexuals ought to be different,” wrote Wendell Ricketts, author of the 1984 study Biological Research on Homosexuality. The best answer we’ve got is something of a tautology: “heterosexuals and homosexuals are considered different because they can be divided into two groups on the basis of the belief that they can be divided into two groups.”

Though the hetero/homo divide seems like an eternal, indestructible fact of nature, it simply isn’t. It’s merely one recent grammar humans have invented to talk about what sex means to us.

Heterosexuality, argues Katz, “is invented within discourse as that which is outside discourse. It’s manufactured in a particular discourse as that which is universal… as that which is outside time.” That is, it’s a construction, but it pretends it isn’t. As any French philosopher or child with a Lego set will tell you, anything that’s been constructed can be deconstructed, as well. If heterosexuality didn’t exist in the past, then it doesn’t need to exist in the future.

I was recently caught off guard by Jane Ward, author of Not Gay, who, during an interview for a piece I wrote on sexual orientation, asked me to think about the future of sexuality. “What would it mean to think about people’s capacity to cultivate their own sexual desires, in the same way we might cultivate a taste for food?” Though some might be wary of allowing for the possibility of sexual fluidity, it’s important to realise that various Born This Way arguments aren’t accepted by the most recent science. Researchers aren’t sure what “causes” homosexuality, and they certainly reject any theories that posit a simple origin, such as a “gay gene.” It’s my opinion that sexual desires, like all our desires, shift and re-orient throughout our lives, and that as they do, they often suggest to us new identities. If this is true, then Ward’s suggestion that we can cultivate sexual preferences seems fitting. (For more of the scientific evidence behind this argument, read BBC Future’s ‘I am gay – but I wasn’t born this way’.)

Beyond Ward’s question is a subtle challenge: If we’re uncomfortable with considering whether and how much power we have over our sexualities, why might that be? Similarly, why might we be uncomfortable with challenging the belief that homosexuality, and by extension heterosexuality, are eternal truths of nature?