Freemartins are intersexed.
Testosterone is powerful stuff even when it's being used by adult transmen, and fetuses are much more sensitive to chemical influences on their development than adults. This is why all the women involved in "on-screen" pairings are fertile females, despite their relatively low representation in the population as a whole - even in designing an anything-goes, hedonistic future society, Huxley couldn't let go of his early 20th century heteronormativity.
Brave New World is intended (at least on some level) to be a satire or deconstruction of the idea of Heaven.
Huxley's dystopia is a place where humans want for nothing, have nothing but feelings of mutual compliance and overwhelming happiness at all times, and no longer fear death. Their children dance and play around the bodies of those who will soon die, almost like Cherubim. This has come after a terrible conflict almost akin to the Rapture, after which the very notions of sin and suffering have been expunged.
Our sympathetic protagonist, John, a man who importantly has some degree of traditional Christian and religious ideals which include the idea of Heaven, is disgusted by this entire scenario. What at first seems like the most beautiful idea imaginable at a distance, feels so wholly alien and distasteful to him as a free-thinking human being that he can't stand to be a part of it. He realises that an existence without scarcity, adversity and trials to triumph over has no meaning, and comes to reject it.
The society depicted in Brave New World is the society that THRUSH
is planning for after it succeeds in its objective of world conquest.
Some highly-placed officials of THRUSH have tried to throw the intrepid Napoleon Solo and Illya Kuryakin
off the track by claiming that their ideal society is based on Orwell's 1984
, but the truth is even more insidious. This society - with all of humanity subjugated to the rule of a tiny oligarchy, strictly hierarchical, technological in nature (the more technology used to pacify the masses, the better, helped along by heaping helpings of sex and consumerism), with anyone over the age of 60 being deemed undesirable and removed with dispatch and any other "undesirables" not necessarily being executed but physically removed to remote islands where they can't disrupt society at large - neatly fits all of THRUSH's objectives.
People who are too smart or innovative are sent to islands. However, Mustapha Mond's comment of "Why, if we didn't have all these islands, we'd probably have to send them to gas chambers!" may make you a little suspicious about the exact nature of these "islands." Especially when Mond mentions the Cyprus experiment, specifically how Cyprus was "cleared of all its existing inhabitants
". Cyprus was an island.
- Alternatively, the inhabitants of Cyprus really were sent elsewhere; Bernard regards being sent to an island as a terrible punishment, but Helmholtz is quite positive about it; he specifically asks to be sent to an island or archipelago, such as the Falklands, with a lousy climate, so that he can have his creativity fired up.
- Mass-murder would go against the whole tone of the book. The whole point of Brave New World was to deconstruct a society that "oppressed" people without the need for any kind of violence or cruelty. Free-thinkers might be regarded as as a threat to society, but the Controllers of the World State don't hate them. They probably would kill them, if there was no other option, but the world is big enough, and the World State productive enough that maintaining a small population of dissidents in a number of isolated, but comfortable locales is entirely feasible. After all, allowing the existence of people who have the necessary mentality to kill their fellow humans for ideological reasons, still less putting them into positions of power, is also a threat to social stability. Exile allows for swift removal of troublemakers, without the risk of the Controllers growing too bloodthirsty. It also keeps out-of-the-box thinkers on hand, just in case an outside context problem ever turns up.
- It's mentioned that when the society was shaping up, they massacred numerous opponents, so it wouldn't be completely unusual. However, they might have viewed this as only necessary then and wouldn't needlessly kill people later on.
- The book does mention the Earth's population to be around two 'thousand million' note , so there are probably an abundance of these islands. Or, seeing as the novel is set in our, current population of seven billion, future, islands.