Folklore has it that many scientists got started on their scientific careers through a childhood interest in science fiction. I am not sure how accurate this is -- in my case, the reverse is true. I began reading science fiction because of a childhood interest in science.
But are most scientists also fans of science fiction? My experience from talking to my colleagues in physics and astronomy over the years suggests that they divide into three roughly-equal groups (this is admittedly an unscientific poll of scientists!) About one-third of my colleagues seem to be avid science fiction fans. This is certainly higher than in the general population, but far from an overwhelming majority. About one-third have never been interested in science fiction. And what of the remaining third? They were science fiction fans as children or teenagers but lost interest as they grew to adulthood. As the famous saying goes, the Golden Age of science fiction is 12.