Fanon

Fanon is a body of popular suppositions and theories accepted by fans concerning the Doctor Who Universe. It is a portmanteau of the words "fan" and "canon".

Fanon often gets confused for "canon", even if it is not supported by on-screen evidence.

Some fanon derives from from non-canon sources such as The Doctor Who Role Playing Game, which, for example, made the Master, the Monk and the War Chief into the same Time Lord.

Some fan theories, such as the Season 6B theory, while not as yet confirmed on screen, have been supported by expanded universe spin-offs such as novels (which are of uncertain canonicity). Others, such as the question raised by DW: Planet of Fire as to whether the Doctor and the Master are actually brothers, have been denied by off-screen sources, if not necessarily on screen.

When stories break fanon conventions, it can cause controversy. A longstanding piece of fanon is the supposition that the Doctor, due to his alien nature, is incapable of romance or sexual attraction. Despite the existence of a granddaughter, and occasional minor references during the early years of the show, much of this supposition stems from the Fourth Doctor's odd reference to Countess Scarlioni in DW: City of Death as "a beautiful woman, probably," as well as the 1963-89 series' general aversion to including romantic entanglements due to its long-standing image as a children's program. The Doctor Who telefilm of 1996 was controversial with some fans because it showed the Eighth Doctor kissing Grace Holloway twice, the latter in an unambiguously romantic way, which was accused of violating canon, even though it only violated fanon. (The revived series has since thoroughly rendered this piece of fanon moot by featuring later Doctors in numerous romantic situations and entanglements.)

An example of fanon stemming from the series revival is the question of "TARDIS coral". Fans have come to use this term to refer to pieces of TARDIS obtained by Jack Harkness (Torchwood) and the Meta-Crisis Tenth Doctor (DW: Journey's End - deleted scene). In fact, as of July 2009 no episode has ever used the term to describe these objects, nor have any close-ups indicated whether they are, indeed, coral-like. The issue is further muddied by the fact the Journey's End reference was deleted from the final episode, raising the question of its canonicity.

When fanon becomes canon
There is precedent for "fanon" to cross over into official "canon". The aforementioned Season 6B theory comes close, having been featured in a BBC Past Doctor Adventures novel and endorsed by former script editor Terrance Dicks (who wrote the book in question, World Game); the BBC has never made a firm proclamation regarding whether novels and other spin-off works should be considered canonical.

In the Star Trek franchise, a recent example of fanon becoming canon involves Lt. Uhura's first name. For decades, fans postulated that it was Nyota, and this was supported by Uhura actress Nichelle Nichols and was also mentioned in numerous novels and comic book spinoffs. However, Trek creator Gene Roddenberry, along with Trek franchise owner Paramount Pictures, set firm rules on what is considered canon in the Trek franchise -- live-action TV and film productions only. But in the 2009 Star Trek film, the name Nyota was used on screen, rendering it canon.