According to Google's content policy, "publishers are not permitted to place Google ads or AdSense for search (AFS) " on pages related to adult content. Such a policy might be comprehensible but, once again, the devil is in the details. Indeed, among a wide list of content considered as "adult violations", you can find the category below:
The consequences of such a restriction might be harmful to public health. Actually, when you consider the last bullet point, it concretely means that no companies -nor NGOs- are allowed to buy ads in order to alert the public and encourage them to adopt a non-dangerous behaviour. For instance, condoms' manufacturers are hence not allowed to buy ads next to sexual health content, whereas that would make the users more sensitive to the necessity to protect themselves. On those topics, Google's current policy also prevents NGOs implied in the fight against AIDS to advertise on content, which are the more likely to be requested by high-risks populations.
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