Famed sexologist Alfred Kinsey called them "group X." Big Bang Theory calls them people who, like Sheldon, "have no deal." But the one percent of the population who aren't interested in sex call themselves asexuals, aces, or, more simply, people who would pick cake over sex.

Asexuality began to emerge in the public sphere as a sexual orientation in the mid-1990s, after a massive study in the UK revealed that 1.05% of people described themselves as having "never felt sexually attracted to anyone at all." Since then, asexuals began to form communities online and in person, trying to create a comfortable place for themselves in a world where sexual indifference is often treated as a defect or disease. Though asexual communities may have precursors in millennia-old celibate religious orders, there is a big difference between choosing celibacy for religious reasons and choosing asexuality because you like cake more than sex.

Asexuality is also a futuristic sexual orientation, represented more often in science fiction than other genres, which may be why some asexuals call the Doctor from Doctor Who their hero.

Unlike homosexuality, which has been stigmatized for centuries in many cultures, asexuality isn't usually greeted with rage or disgust. Most often, say asexuals, the problem is that people don't realize that asexuality is — as the characters in Big Bang Theory put it — "a deal." Even when people do stumble across asexuality, there are a lot of misunderstandings about what it means.

Paul Cox, an asexual who is happily married to another asexual, wrote in The Guardian about what it was like to go through puberty as an asexual:

When I was 13, my father gave me a book on sex education. I felt as if I was reading about a foreign culture; I just couldn't see why anyone would go to so much trouble just to have sex. I tried looking at pornography on the internet. I wasn't disgusted or appalled - it was just boring, like looking at wallpaper.

Masturbation was another topic of conversation in those days, and I did masturbate. It wasn't a sexual urge for me, I didn't fantasise, it was just something my body decided to do. People say about asexuals: "But if they masturbate doesn't that make them sexual?" It's hard to explain, but if you're asexual you don't necessarily feel an explicit connection between masturbation and sexual orientation. It's just part of having a human body - a physical, biological process.

Later, Cox describes discovering the asexual community through the message boards at Asexuality.org, and at last coming out as an asexual. Once he realized he wasn't alone, he began exploring what it meant to have relationships without sex. When he met his future wife through an asexual group online, he discovered that he wanted a romantic, long-term relationship.

And Cox realized, as many asexuals do, that a lack of sexual desire doesn't foreclose the possibility of marriage. It just means that the marriage won't be conventional. On their wedding night, Cox and his wife stayed up late with their friends playing Scrabble in the honeymoon suite.

Science fiction writers from Kurt Vonnegut and Karen Healey to Greg Egan and Elizabeth Bear have written about characters who identify as asexual, and the idea of becoming asexual for the good of a space colony is played for weirdness in Bruce Sterling's Schismatrix. Asexuals also romp through the post-human worlds of Iain M. Banks and Charles Stross.

I'd suggest there are two main reasons why SF authors have written asexuals into their future societies. First of all, many authors imagine that humans of the future will be completely liberated from the need to reproduce biologically, using seriously retrograde penis/vagina methods. Once the species can reproduce using biotechnology, we are freed up to explore the idea that maybe not everybody wants or needs to have sex, and so asexuals will become an ordinary part of any post-human society. The second reason I think that asexuality figures into science fiction is that asexual relationships themselves free humans from the traditional constraints imposed on romantic couplings. If you don't base your most intimate relationships on sex, then you're able to reimagine human intimacy in all kinds of new ways.

And indeed, this is precisely what asexuals are doing right now.

Over at Kitch Magazine, Helen Havlak profiles Alexis, an asexual college student who is very active in online communities like AVEN (the Asexuality Visibility and Education Network). Alexis talks about how Doctor Who's time traveler is one of the heroes of the asexual community, because he has incredibly close friendships with people but seems mostly uninterested in sex. Havlak emphasizes that one of the benefits of asexuality is being able to embrace friendships as central emotional connections:

Overall, Alexis said, many asexual relationships don't differ all that much from a "normal" sexual relationship. Open relationships do tend to be a greater presence on AVEN than in the general public, though, and many asexuals have more fluid life plans than getting married and having kids at a certain age. "Some people re-adopt that plan later," Alexis said, "but on their own terms."

One perk of identifying as asexual, Alexis told me, is that many people find that "discovering their asexuality liberated them from feeling like they had to be held up to certain standards, and it helped them become much closer to a lot of their friends, in that they started treating their relationships more like friendships, and their friendships more like relationships." She clarified, "In a certain way, they try to remove the ‘just' in front of ‘just friends,' because no, a friendship does not have to be in any way a lesser kind of relationship than a romantic one. Society makes you think that your goal in life is to find a specific romantic relationship. And ultimately, we should build emotionally close relationships with everyone around us."

Just as homosexuals are helping to redefine what marriage means, asexuals are helping to redefine friendship. And they are becoming a stronger, more visible group in the process.