This has been brought up before, but it's been a while and there was limited information about what version is what; so in order to serve my children best since they have to do a report on it next year, I looked around to see what I could find.
I didn't want my son reading about the sexual thought life of a pre-teen girl (well, my dd either for that matter).
So far, this is what I've discovered:
Otto Frank had about 30% edited out of the original 1947 Dutch language version; sexual thoughts of a girl going through puberty, severely negative comments about her mother and her parent's relationship, as well as observations and negative comments about the other family.
An English version was published in 1952 based upon the edited version of 1947. The book remained that way until 1989 with the release of the original, unedited diary in The Diary of Anne Frank: The Critical Edition
Then in 1991 came Anne Frank: The Diary of a Young Girl - The Definitive Edition w/Susan Massotty as translating the unedited passages in this version.
Then in 2003 came The Diary of Anne Frank: The Revised Critical Edition; again containing the extra material.
There have been gov't. school systems where parents have complained about the Definitive edition being used and the school ahd to go back to the older versions.
So that's all I've been able to find out. If you want the edited version, you'll need to seek out versions published prior to 1989 and without Susan Massotty on the cover as translator or any other versions that speak about the editing process. For example, I have a copy published in the 70's, based on the 1952 english version, interoduced by Eleanor Roosevelt and it has a page in the back informing you that there was editing invovled-so it's good.
Hope this helps you make an informed choice for this important piece of history and personal story.