Google ads may not be placed on content that provides tips regarding sexual performance or discusses some treatments of sexual health issues. Examples include, but are not limited to:
- advice about improving sexual performance
- discussions and/or images of sexually transmitted diseases
- sexual health advice related to pregnancy, childbirth, or family planning
I don't see it in the policies right now, but I believe that you can stay within their guidelines by not placing ads on the pages with prohibited content, or on the pages that link to those page. So you can still have AdSense on the rest of your site, just not where the Ads would appear within one click from adult content.
Google has put together a presentation about their adult content policies for AdSense and you can watch it on Youtube. The presentation is about half an hour long, but it goes into a lot of detail and really explains their policies.