Gender segregation has become seen as rather outdated. In Britain, where the old Victorian school buildings still carry the words "boys" and "girls" once indicating separate entrances lest the children be tempted to indulge in beastliness, the Conservative government has just announced that any citizen may identify as whatever gender they choose. This mirrors the War of the Bathroom in the U.S., which has of late spread to the military and where increasingly any all male-gathering in politics — especially of the pinkish variety — is liable to be dismissed as illegitimate by definition. And yet politics has become sex-segregated as never before, which partly explains its growing extremism.

It's not widely known, but there once was a time in Europe when clothes weren't gendered. There were no "men's clothes" and no "women's clothes" and most people below the aristocracy wore pretty much the same thing, or at least the differences were small.

Then in the 13th century something came along that changed everything — the button. Men and women began to dress in a way that emphasized masculine and feminine physical characteristics, and it was a still recent enough change at the time of the Black Death in 1348 that many observers blamed the disease on these new tight-fitting outfits. One chronicler attacked men's clothes "cutted on the buttok" which "inflame women with lecherous desires"; another complained that English women "dress in clothes that are so tight ... they [have to wear] a fox tail hanging down inside of their skirts to hide their arses." All of this had brought the Almighty's wrath crashing down on us.

In the late 20th century a similar thing happened with a number of products on the market, among them children's toys. When Lego first came out, your options were basically a Lego set or a slightly different Lego set; even when I was very young in the 1980s the spaceman was about as complex as it got. But today you have a vast range of options, including Star Wars Lego, Batman Lego, princesses, knights, aliens, and everything under the sun. And the more diverse these toys get, the more gendered they become, because toy-sellers are able to target more specific demographics, sex along with age being one of the most effective categorizations.

Likewise with grown-ups. As we become freer, and our lives more complex, most people tend to become less gender fluid, not more: So the more liberal a country, the greater the difference between the sexes in their choice of professions, while more gender liberal countries also have larger sex differences in math scores.

The more freedom we have, the more there will be very feminine and masculine subcultures too, and this might explain a great deal of recent political developments — in particular the campus identity politics movement and the alt-right. The former is heavily female, while the latter is overwhelmingly male — in fact, not just male, but populated by men who seem to have difficulties with women.

Although there are numerous factors accounting for these two broad developments, it could also be that they are just the political equivalent of the Lego Friends Heartlake Cupcake Cafe and the Lego Nexo Knight's Clay's Falcon Fighter Blaster, examples of where greater freedom of association and self-actualization has led men and women to form into more gendered political groups.

Single women tend to be politically very liberal, voting for the Democrats in huge numbers, while in Britain Labour Party leader Jeremy Corbyn has overwhelming support among young women, the vast majority of whom are unmarried. Generally speaking, the culture wars are far more intense between women because women have to make more sacrifices — whether children or career — and this inevitably influences their worldview. Political liberalism, with its strong relationship between the state and the individual, favors single women, while conservatism, with its emphasis on monogamy and support for the nuclear family, speaks to their married equivalents. And while married men with children are also more conservative than single ones, the difference is not as pronounced.

So what happens when fewer people get married and, indeed, spend time with the opposite sex? Gender-segregated politics it seems.

In recent years there has been a steep rise in the proportion of female students, especially in the humanities, to such an extent that the imbalance has led to a shortage of marriageable men.

It would seem logical, therefore, that already heavily left-leaning institutions filled with single women would be the perfect breeding ground for a forceful progressive movement, one in which members are in competition to display their political zeal.

In contrast, increasing numbers of men are moving into all-male worlds by dropping out of dating altogether. So while compared to Generation X, a larger proportion of millennials are engaging in more promiscuous sex, a larger number of them are also having no sex at all.

Freedom leads to sexual divergence — even in political movements.

The online alt-right grew out of subcultures that were already heavily male, where excess, angry men made ideal recruits to a cause — something noticed long ago by Stephen Bannon during his venture into World of Warcraft, when the future Breitbart boss said that "these guys, these rootless, white males, had monster power."

And anecdotally, a lot of men who do partner up become more politically liberal or moderate, perhaps under female influence or perhaps because the Islamification of the West doesn't seem like such a pressing issue when you have an actual girlfriend. And yet, modern life allows men to avoid pairing off altogether, once almost the only socially acceptable route available to them, and so these political subcultures are likely to continue to diverge.

And I haven't even got onto the subject of sex robots.