But it's not that simple.
Even if a writer is unaware of asexuality as an orientation (you know, the kind that affects real people), the writer can still write "asexual" characters, in the sense that they seem uninterested in sex or relationships. There are some pretty obvious reasons to write such a character. Maybe it's just too hard to write sexuality well. Maybe it wouldn't fit into the story or mood. Maybe it's just to serious a topic to get into.
Or maybe the lack of sexual interest is intentionally meant as a character quirk. Here are a few well-known examples.
Sherlock Holmes is portrayed as a cold calculating deductive machine. Where does an emotion such as love fit in? According to Sir Arthur Conan Doyle (and many other writers) it doesn't. In the recent film with Robert Downey Jr., I think he was rather asexy too. Okay, so there was a fair bit of innuendo between him and Watson, but I think that was more for laughs than for anything else.
The Doctor always takes with him a companion, usually female, on his time-traveling adventures. But he's never shown any romantic interest in any of them (apparently this is somewhat questionable in the newer series). Personally I think the writers just like to leave the shippers in a state of permanent speculation. But it also makes sense because the Doctor is an alien. Do aliens count as asexuals? For that matter, do robots? Holograms? Zombies? Sponges? These sorts of questions are absolutely important and/or completely pointless!
Dexter, the serial killer with his own TV series. Not interested in sex, at least not in the books. This is what I've been told, anyways. I've never actually read the books or watched the show for that matter.
Sheldon Cooper is theoretical physicist at Caltech, and the most popular character of a sitcom called The Big Bang Theory. He's portrayed as utterly oblivious to any sexual or romantic cues. Social cues too. In fact, he seems to be autistic. I wonder if the autistic community is happy with his portrayal.
The following dialogue is basically the closest thing to identifying Sheldon as asexual.
But since it's a TV show with many writers, you can never guarantee that Sheldon's character will be static.Penny: I know this is none of my business, but I just... I have to ask — what's Sheldon's deal?Leonard: What do you mean, "deal"?Penny: You know, like, what's his deal? Is it girls...? Guys...? Sock puppets...?Leonard: Honestly, we've been operating under the assumption that he has no deal.
Have you noticed? Sheldon is an asexual physicist, and so am I! In theory, I should closely relate to him. Except... I'm not really autistic at all. And more importantly, he's part of a sitcom that I think is boring.
There are all sorts of cynical things I can say about the above portrayals. I mean, asexuals are either aliens, psychopaths, or untouchable geniuses. On the other hand, the only people who insisted on labeling them as asexual were me and parts of the asexual community. Obviously, we must derive some enjoyment from the speculation. Perhaps we think that a stereotype is better than no portrayal at all.
Are there any self-identified asexual characters in major media? Yes, there are! I mean, is. There's one. I give you Gerald Tippett.
Gerald Tippett is a character in a New Zealand soap opera called Shortland Street. In 2008, there was a whole storyline where he came out as asexual. All the relevant clips have been collected on YouTube.
Once you have a self-identified asexual character, there are several very obvious storylines which pretty much write themselves (at least if you're familiar with the subject). Gerald cycles through basically all of them. He starts out as a twenty-something whom everyone suspects is gay. He discovers asexuality while in the middle of a relationship. He doesn't accept it at first, asks for a cure. His girlfriend doesn't accept it at first, tries to interpret every quirk as a possible cause. His sex-positive mother discovers that there is one form of sexual deviancy that she just can't accept (awkward dinner follows). The coworkers find out and become busybodies. Gerald tries a meetup group. Gerald tries an open relationship. Oh, and there's a perpetual love triangle too.
In some possible future, these stories are absolutely trite. But right now, they're absolutely unique and wonderful. I loved it. Maybe it's just me because I'm asexual? Is it a complete bore for everyone else?
If we compare Gerald to any of the other characters I mentioned, there's a vast difference. He's an ordinary character, not an extraordinary one. He's heteroromantic (or biromantic), not aromantic. His asexuality is not just another personality quirk, but brings up many difficult issues like identity, social acceptance, asexual/sexual relationships, and so forth.
After a while, the asexuality storyline dropped to the background, and it turned into some ridiculously soapy story about Morgan being a surrogate mother or something like that. I couldn't watch it after that.