I understand this might be a sensitive and controversial issue, but having just re-read it as an adult (read it many years ago in school), I couldn't help but feel that every single page had the scent of a grown man. I did some reading and discovered two things that alarmed me. Firstly, the fact that Anne's father was said to have "edited" all of the diaries into one cohesive book (this in itself is an understandable requirement), but the other thing was that he had apparently removed many references Anne made that were of a sexual nature (masturbation, etc).
Really though, reading through it, I just don't buy for a second that the words in the diary were written by a 15 year old. I've Googled this, but I'm being led to a lot of websites that seem "politically/racially charged" to say the least, so I thought I'd ask here.
Despite this, I maintain that the books are an essential read for an adult, but ultimately, my question is, what proof do we have, if any, that it was actually Anne Frank that wrote the diaries, and not just her father?
There's absolutely no doubt that Anne Frank wrote a diary during the war, or that she rewrote portions of it in 1944, or that it was edited for publication by her father (and in fact that there are a few editions of it). You can read more about this in the answers to older thread by u/commiespaceinvader.