Since social engineers have come up with the idea of building new, multi-racial, multi-national, multi-religious, multi-cultural societies, they have encountered the natural barrier: xenophobia, which is another name for in-group loyalty and out-group avoidance. Xenophobia is a biological mechanism imprinted at the genetic level that carries a survival advantage. It tells an individual to create bonds with members of the same group and be on his guard against aliens.3)To put it in plain language: xenophobia is practised at the very basic personal level each time parents warn their offspring to be wary of strangers: not to open the door to them, not to trust them. So modern social engineers have a problem. They need to overcome this deeply rooted biological barrier.