From the Wikibooks page 
Claude Martin claims that the Voynich Manuscript would contain a phoney text, based on numeric sequences transcribed into anagrams. For example, a line forged on sequence 345678 would be retranscribed into 643875. This « fill in text method » would be used to produce text having some semantic similarities with a real text.
His website, in French, is .
The counter-arguments would include (even if 'the usual problems' with resolving anagrams are ignored for this purpose) the amount of time and work required to generate the text of several hundred pages and in a form that resembles 'an ordinary written text' of the period (and also the cost of the materials and absence of draft versions).