Now... Hear me out.
Say there's a... very specific pair of images involving a guy shagging another... character. Problem is, while thanks to what they're doing, one of them is clearly male... the genitalia of the other character is not visible. Plus, this second character doesn't have any obvious breasts. The artist perhaps intended for it to be a guy, perhaps intended for it to be a girl, it's not immediately clear just from looking at the image. (No, eyelashes do not make a girl, traps and twinks are a very, very established thing in this fandom. The Girly tag exists for a reason.)
Two people want to search for pictures- say, a straight guy named Jim, and a gay guy named Mike.
Jim has blocked "m/m" pictures, because he doesn't want to see a picture of a guy shagging a guy- he's perfectly straight, after all. However, Jim is perfectly fine with a guy shagging a character whose gender is unclear, as they can just assume it's a girl.
Mike has similarly blocked "m/f" pictures, because he doesn't want to see a picture of a guy fucking a girl- he's very, very gay, after all. However, once again, Mike is perfectly fine with a guy fucking a character whose gender is unclear, as they can just assume it's a guy.
Under the current interpretation of the rules, the pic would be tagged "m/f"- thus, Jim could find it just fine, but it would end up blocked by Mike's filter. Which would get (and has gotten) especially awkward if the artist, let's call her Mary, really did intend for it to be m/m.
The solution? Simple: Just tag it m/a, or Male/Ambiguous. When people can argue (and HAVE argued) on and on about whether a character is male or female, the obvious solution isn't to come down on one side or the other- it's to tag it as "ambiguous", and call it a day. This would make BOTH sides happy, and would jibe perfectly well with Tag What You See (after all, Ambiguous is for situations where *you can't tell one way or the other*)
But Lunamann, I hear you say. The Tagging Genders guide already says to look to body shape to determine gender, if you can't see genitalia! The problem is, my friend, that line of logic is not TWYS. It's "Tag What You can Infer", or as I'll abbreviate it, TWYI. And TWYI, not TWYS, is what spawned this TWYS vs TWYK argument in the first place. And my solution, is to enforce TWYS even harder, by squashing the TWYI mentality championed by "look to body shape to determine gender", and instead adding two new tags for this situation, both of them implying the Ambiguous gender.
Masculine_Ambiguous, for when the body type of a character is clearly masculine, but you can't see genitalia or breasts.
Feminine_Ambiguous, for when the body type of a character is clearly feminine, but you can't see genitalia or breasts.
Under *this* new system, the pic would be tagged as "Feminine_Ambiguous, Ambiguous, Ambiguous/Male". Mike would be happy, because he could finally see this pic that is (to him) clearly a guy fucking a guy, without disabling his filters. And Jim would be happy, too, because he'd still be able to see the pic that is (to him) clearly a guy fucking a girl. And Charles, who isn't interested in seeing feminine_ambiguous characters but still wants to see masculine_ambiguous characters, can now put feminine_ambiguous on his filter and be even happier. And Mary would be... probably happier with this situation. After all, the tags wouldn't be completely wrong according to her intent anymore- yeah, you *can't* tell whether this character is male or female in this pic, and yeah, the character *does* have a feminine body shape. Sure, not all the information is there, but that's pretty much the norm with TWYS, isn't it?
Updated by NotMeNotYou