This discussion of DID is highly problematic in a few ways. I have tried to remove references to multiple personality disorder (an old name, no longer used, and disliked by the DID community) and to multiple personalities (alters is the preferred term). The discussion of how systems form also acknowledges a debate in how it happens, which does not exist in the professional community—doctors agree DID is caused by trauma and traumagenic systems find the idea that DID could be caused by non-abuse-related methods uncomfortable. Furthermore, the discussion ignores much of what people with DID know about co-consciousness, how amnesia works in cases of DID, and the fact that DID is primarily marked by dissociation, not by having alters. I would recommend deleting the entire section, as it seems unnecessary. I have put the discussion here in case someone with the disorder wants to go through it and remove the problematic content. "Dissociative Identity Disorder, previously called Multiple Personality Disorder (MPD). In DID, a switch between personalities means that the other personality isn't aware of the amount of time or things that happen while they weren't the one who was active. When the other personality switches back, they don't remember what happened during that time. That's called a blackout or lost time, and it's the main thing that makes DID risky. The main difference between gender fluidity and DID is that genderfluid people don't have these blackouts. Another difference is that DID is usually thought to be caused by a traumatic experience, such as having been abused as a child. (However, this is debated. It isn't certain that all cases of DID have an origin in trauma.) Genderfluidity isn't caused by trauma. Another thing that makes trouble in DID is that the personalities can't communicate with one another.
A healthy form of multiple personalities isn't formally recognized by psychology, but there is a community of people who say they have healthy multiplicity or plurality. Personalities within a healthy plural system don't experience lost time, have worked out living agreements similar to house rules, can communicate with one another, and are on friendly terms with one another. A typical case of DID has none of these characteristics, and these characteristics make it possible for a healthy plural system to function well. This is a sign that multiplicity can be just another way that some people's minds work, in the wide spectrum of neurodiversity.
If someone is considering that their gender fluidity might be like DID or multiplicity, this characteristic is important: "Everybody has different sides to their personality. The difference is that multiplicity involves distinct persons with their own full range of thoughts and emotions, including their own various sides of themselves as well." Even a genderfluid person who has different personas for each gender doesn't necessarily experience these personas as being whole different people, but just as different aspects of their one self. In that case, it isn't much like DID or multiplicity.
In some cases, there is little difference between a genderfluid person who has different personas for each gender, and healthy multiplicity. Genderfluid people of this kind could find that resources created for healthy multiple systems are helpful for themselves as well.
I just made an account because I thought it would be worth adding a couple of notes on the history of the term from the OED: it goes back to at least 1987, discussing the gender of God; a 1993 publication used it in something like the modern sense, to describe the audience at a Suede gig. --Oolong (talk) 14:14, 30 September 2019 (UTC)