there's nothing here :)

There are several claims that Gencest predates 2009. Unfortunately, these discussions were in 2018, and between then and now I am unable to corroborate their existence or find any evidence of them.

(Expect discourse if you click on any of the source links.)

from this post on tumblr:

Less than 2 pages on Ao3 (2 works 05-06, a few 2012, mostly 2015+)

from this tweet:

and from replies in this post:

(There exist other examples of the 2006 claim but @/gencest on tumblr is also @/GencestBang on Twitter so it's not necessary to repeat that.)

LiveJournal search results, Tumblr search results, and Twitter search results all track back to 2011 at the earliest, possibly just because of how much linkrot must have happened, so I can't corroborate any activity pre-2011 besides musesfool's directly linked 2009 post.

However, the earliest fics on Ao3 were published September 13th, 2008, meaning that any fics using the Gencest tag, even if backdated to 2005-2007, may have just retroactively added the Gencest tag when it became known to them, especially since the first fic to actually use the Gencest tag on Ao3 is Respite by sailoreyes67, in 2012 (info here), and the oldest search result for Gencest in general is Prayer Bundles by quickreaver, also in 2012.

It's entirely possible musesfool's post is simply the only thing that survived and that other pockets of fandom used Gencest before spectralbovine, but for a lack of any other immediately-accessible evidence, I feel pretty confident in listing 2009 as a starting point, if not the starting point.

Through early-mid 2010s fandom

Despite the 2009 post, though, I fail to find any records of Gencest being used in 2010. As stated, LiveJournal's search results for Gencest only go as far back as a June 2011 post by quickreaver, who is also the earliest surviving Twitter record in 2011, and also the earliest surviving Tumblr record, also in 2011. (There's room to say it was a retroactive tag re: Tumblr, though given the Twitter and LJ entries it wouldn't be that big of a deal if it was.)

Regardless, between 2011 and 2018, most of the Gencest discussion on LiveJournal is varying tags for fic and a few people trying to find stories by describing them as such. The tag on Tumblr largely goes unused with about one post every few years. Over on Ao3 it garnered around 24 fics in that timeframe (discounting the most obvious retroactive tags when the Gencest tag became canon, though ofc, I can't attest to this accuracy.) Twitter conversation exists, but is sparse through the years.

A blip in all this is Jules Wilkinson's contribution to the book "Fic: Why Fanfiction is Taking Over the World" is published in 2013 by Annie Elizabeth Jamison.

From page 310 (or so I'm told by the book's index since this is a digital copy...):

Wilkinson is missyjack on LiveJournal, who in 2012 made this thread in part related to the yet-to-be published essay to gauge some opinions. They ask a number of things, including whether or not people know what Gencest/hard gen means. Some people do, some people don't. Still, a neat look into the fandom at the time!

The Big Bang

After several years of consistent but sparse activity, in July 2018, Gencest Bang posts an overview for their event on LiveJournal, and signups open later in November. The Bang posts in April 2019, and is held again in 2020. The event prompts discussion, positive and negative, but usage of the tag increases.

(Personal conjecture: the finale probably helped too 😂)

In 2021, a separate event is started by the SPN Gencest Bang in absence of the original mod, and the SPN Gencest Bang continued to host yearly events in 2022 and 2023.

How We Got Here

A lot of things we associate with being typically romantic/sexual... are purely culture specific. Hugging isn't inherently romantic. Sharing a bed isn't inherently romantic. Deciding to spend the rest of your life with someone isn't inherently romantic.

This was pretty much covered by the revival of Gencest, where you got fics where Sam and Dean can be platonic life partners and be very close and emotional with each other and it's not considered Wincest.

But there's still more to that whole "not inherently romantic/sexual" thing.

Namely, kink isn't inherently sexual, sex isn't inherently romantic, and kissing on the mouth can be platonic.

In real life you’ll find kink/BDSM involves less actual sex than pop culture and fanfic would have you believe, especially for asexual kinksters, and in fandom we have platonic sex, platonic kissing, platonic romance (which “platonic marriage” redirects to), platonic BDSM, non-sexual bondage, and non-sexual submission, all of which are all canonical Ao3 tags.

So, in early 2021, discussions started on “platonic [something that isn’t typically viewed as platonic]”.

It usually involved non-sexual kink or things associated with romance. Things like platonic hickeys, kissing, hairpulling, biting, kissing, gunsucking, even more kissing, bootlicking, what have you.

So there was obviously a possible niche for Sam and Dean feeling completely platonic about each other, but still doing things that are not what you'd expect to be platonic relationship, especially not one between brothers.

Now the problem was, what do we call this niche?

Why it's Not Called Gencest

Gencest is already a very rare thing in fandom for being unironically (queer)platonic, with Sam and Dean being both each other’s focus and typically the story’s focus. Itself has (had?) its controversy, but by 2021 the debate had pretty much died down, partially in thanks to the annual Gencest Bang, so some early non-sexual kink fics used the Gencest tag, including my own.

I run off two specific definitions of incest, and that’s either the dictionary definition (involves sexual elements) or the emotional/covert definition (which has irl criteria that Sam and Dean don't usually fulfil and so isn't relevant here).

And since Sam and Dean didn’t touch each other’s dicks or get any sexual satisfaction out of non-sexual kink, and it’s not implied that off-screen they were doing that between all that platonic kissing, you could by extreme technicality call that Gencest because they were platonic.

But like, it was probably best not to.

Within the framework of fiction and fandom, incest is not defined by just by the characters having committing incest via sex, on-screen or off-screen. Wincest is still tagged Wincest even if it's non-sexual and SFW.

So for the purpose of being able to blacklist for people who were squicked out by incest, it could not and should not be folded into Gencest.

But for the purpose of being to find this niche premise, it also could not be folded into Wincest.

Why it's Not Called Wincest

Weirdcest, on premise, does not involve the characters being attracted to each other romantically/sexually. They're not in denial, they're not oblivious, they're not slowly developing feelings for each other over the course of the story, they simply don't have those feelings for each other to begin with.

And that is not what most people expect from romantic/sexual ship tags.

If a character says "nah I don't feel that way" and the fic doesn't include aspec characters, unrequited love, or consent issues, you assume the fic is going to end with them realising they DO feel that way.

So using the Wincest tag would be a surefire way to never be able to find "Wincest but they're not attracted to each other" in the sea of "Wincest but they are attracted to each other because that's the default expectation because that's how shipping culture works".

Not to mention people who ARE trying to find "Wincest but they're attracted to each other" would probably just be confused why there's content tagged as Wincest that's like "this is platonic".

The Secret Third Thing

So you have posts about non-sexual kink and posts about platonic kissing and a secret third thing which is "joking about things that seem like Wincest but technically aren't because Sam and Dean are unironically platonic".

Putting it in the Gencest tag would probably annoy people who are okay with a little bit of "mistaken for incest" humour as per the show canon but probably aren't comfortable with Dean extensively calling Sam his wife or something.

And putting it in the Wincest tag would, again, be super annoying when the punchline is that they're not even incestuous.

Now, should Weirdcest nevertheless be tagged as "sibling incest" for content warning and search purposes, because as stated earlier incest as defined in fandom is much broader than the dictionary definition?

Well. The Dean Winchester/Sam Winchester Ao3 tag has a whopping 19.7% rate of being tagged with some variation of "incest", so in my opinion it should be assumed that just tagging your fic as Weirdcest warns the reader that they have to be okay with incest, subtext or otherwise.

(And of course, not everyone is going to know what Weirdcest means at a glance, but frankly if there's anything Ao3 fanfic has taught me it's that if you don't know what a tag means you should really Google it.)

As for whether it should be tagged as "Dean Winchester/Sam Winchester" or "Dean Winchester & Sam Winchester", or if it should be tagged M/M or Gen or Other... Your guess is as good as mine. I have no idea! (If they are committing sexual incest it goes straight in the '/' category though.)

Conclusion

Weirdcest doesn’t have a distinction for everyone, and not everyone has to use the tag. It was named solely to express the very specific premise of “they don’t feel attracted to each other, but this is not going to be typical platonic behaviour as fandom and real life tends to understand it” and to avoid altering the established expectation of the Wincest and Gencest tags, as well as for ease of searching.

Bonus Round: Things the Weirdcest Tag Does Not Mean

anything “weird” in general

Sam and Dean already set the bar fairly high in canon, and Gencest can be weird too! The "weird" prefix simply owes itself to prince-of-elsinore's weirdchesters tag.

must involve kink or (implied) sexual content

Like I said above, I used it a number of times for "it's not Wincest as a punchline", but it probably wouldn't seem as funny to Gencest-specific or Wincest-specific fans, so into the Weirdcest zone it goes, where everyone will know the nuances.

avoiding being grouped with Wincest shippers