Io9 , an SF-oriented website that covers a variety of ground, did an unscientific poll of Doctor Who and Star Trek fans, focusing on their ambitions, their careers, as well as other data. You can find their results here.
Though not scientific by any means, it’s still interesting reading to speculate on the psychological, economic, and career issues involved – as well as chicken-or-egg issues of what interests come when. I myself, who started as a young SF fan, can’t remember if his interest in science-fiction or his interest in science came first – but I think it was my interest in science.
– Steven Savage