In the AdSense TOS one of the restrictions is against "Adult/Mature Related content" This is so broad. Obviously pornography, nude photos, etc would be against the guidelines. But who determines if its "Adult or Mature" related. Are sites that are focused on improving sexual health. (better sex lives, etc) considered mature. I would assume so. but need clarification
Did you read the detailed information in the Adsense help site? Any content that isn't "family safe" is not allowed, including any sex talk. https://www.google.com/adsense/support/bin/answer.py?hl=en&answer=105957