According to the New York Times and the Anne Frank House there were 5 pages that were missing when the diary was originally published. The five pages have been authenticated as a part of Anne's diary (Anne Frank House)

It seems like there were three versions. Version A is the original diary that Anne wrote. Version B is a version of the diary that Anne rewrote. And Version C is a version that her father put together. In 1998 five pages were found, that Otto, Anne's father had. These pages (at least according to the Anne Frank House and the New York Times article linked above) were not sexual in nature but it is where Anne thought about and criticized her parent's relationship.

According to the New York Times:

In the new-found entries -- actually five pages of diary revisions >censored by Anne's father, Otto -- Anne picks apart her parents' strained marriage, analyzes her own difficult relations with her >mother, Edith, and vows to keep the diary out of her family's hands as ''none of their business.''

So according to these two sources there were parts left out of the diary but they don't seem to be sexual. However, The Diary of Anne Frank is challenged and attempted to be banned as recently as [2010] (http://www.ala.org/advocacy/sites/ala.org.advocacy/files/content/banned/bannedbooksweek/ideasandresources/free_downloads/2011banned.pdf) (see page 5) due to:

...the complaint that the book includes sexual material and homosexual themes.

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