Can I publish "true" stories about my childhood without my family suing me for defamation?

First, anyone can sue for anything. The question is, can they prevail? If you have problems with the members of your family and you believe that they may sue to prevent release of the book you should obtain releases.

The family members might sue you for defamation, invasion of privacy, etc. What you think if as "true," they may think is false. However, there are many fine books written about peoples' miserable childhoods. Usually these are done using a good editor, a good publishing company, a knowledgeable legal team, and solid E&O insurance.

Nothing can prevent one person from suing another. However, if you can provide independent documentation of every fact that you include in your story, you can win a defamation suit. Most autobiographies seem to try to avoid moral judgements and let the readers come to their own conclusions.