No, nor should there be. If we can't think about things we can't rationally determine harms OR benefits, and decide what to [dis]allow. There's a place for some activities to be taboo (though not nearly as many as some people think) but the minute taboos are applied to thoughts and conversations, we're screwing ourselves as a society.

Hmm.. Not really. As long as it's academic my friends and I are willing to entertain just about any conversation or hypothetical. Cannibalism, pedophilia, politics, long as it's academic and the participants aren't too sensitive and understand that discussion of a topic is not an endorsement