I don't know much about the theories, except the ones publicly known about alienstuff. But a former girl friend of mine, spent some time on a raellian camp and she told me there was a lot of sex involved. Everybody being naked a lot and being encouraged (not forced though) to have as much sex as possible with everybody in order to allow the aliens to be born in a human women. She got discuss
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"Cults," Sects, and "New Religious Movements"