ok let's put in another way-
the more "free" the people feel, such as in a democracy, even like ancient greek, the more it is likely they will start think weird stuff and try new things
they have been around forever but on really low amounts
the freeier the world is, the more of them show
i would actually believe nature has a big part behind it
humans multiply too fast at times of peace as no war kills them, for those durations of time, nature has to take action by selecting people and stopping their family trees with them.
heh... maybe nature should be let go with it, there are too many people as is, but being doomed sounds kinda bad, shame they don't realize that nature is just playing tricks on them >>
the reasons i stated before just help that thing spread maybe even above nature's original plan.