What's the best way to avoid this? Cleaning my sites of the word "teen" would be... impossible. How are people still using adwords with this in place?
Well, I mean do you have teen-adult-related content on your web site or what? Do you mind sharing the url? You can start by changing your header information(meta title, descriptions, keyword) on your pages and explain in the most clean way what your web site is about.
'and explain in the most clean way what your web site is about.' .... I quite like this encyclopedic approach to teen porn....
Does your site contain teen porn? Google will know the difference between teen porn and teen magazines, or teen ringtones. Google does not take a single word and make it represent an entire site. It take a holistic view to theme your site.