I was to knew science-fiction is written for the most by writers that actually might have a PhD, or even more than one. That's also what characterizes a little apart this genre (imho, not saying other are less or anything like that, just meaning it's peculiar, meaning at the fictions' books).
What I wasn't to know is that, other than the old school and the recent ones (I would like both) there is a line in-between, as in the preface of the book I'm reading, the editor mentions how the generation within Asimov and Heinlein didn't keep on with the changes, e.g. when science had new topics (biochemistry, genetics engeenering, and what changed in those times on other studies too - astronomy, electonics..), while like persons like van Voght would build up it anyway.
And I'm impressed on what and how many PhD's are in there, too I wasn't to think that several ones did
just went in Vietnam on those times (Joe Haldeman, "The forever War"- 1972 is the one I'm reading, were the preface mentions this topics).
William C.Dietz was a Marine, Cordwainer Smith worked on Intelligence, Elizabeth Moon was a Marine, in Vietam, a PhD in History and one in Biology.
On a book from Mary Robinette Kowal, she asked suggestions to Bobak Ferdowski (flight engineer at NASA's), Derek Bentoski (pilot), and several others.
That's one thing I like from sci-fi, that didn't mentioned and that I wasn't even to guess it was like so (I was stuck in Asimov's, and yet it was fine
).