Do science fiction actors get typecast?

Image via Wikipedia I was relaxing the other day and watching a rerun of The Outer Limits (The new version and not the original) when I saw the actress Nicole de Boer. The episode was called Monster and made in 1998. Well, since I am a total Star Trek geek (ok, I admit it, I am a Sci Fi geek!)I immediately recognized her as Ezri Dax, the Trill who was in season 7 of Star Trek Deep Space 9. She worked on that show for its final season in 1999. Then I saw her in Stephen King's The Dead Zone for several years. She has also appeared in the series Stargate Atlantis. I became so intrigued that I looked her up on IMDb and noticed she has made several other shows and movies in the fantasy/sci fi realm.
This got me thinking about other actors I have seen in science fiction shows. The hunky Scott Bakula was in Quantum Leap and later in Star Trek Enterprise; Brent Spiner has appeared in a variety of movies and shows but is most famous for his role of Data in The Next Generation and later Dr. Soong in Star Trek Enterprise. We could really have six degrees of separation between sci fi actors. For example, Patrick Stewart who starred in X-Men along with Ian McKellen who ironically made the movie Six Degrees of Separation in which appeared Anthony Michael Hall who was later in The Dead Zone with Nicole de Boer who worked with Avery Brooks who appeared with Patrick Stewart. (I know this is a short version of the six degrees, but I am way off topic here.)
I know that is just a fun game to play, but in all seriousness, it seems that once an actor is successful in the sci fi genre, they seem to be placed in that type of role. I don't mind as long as the actor is good and makes me believe they are the new alien or hero in the new series.
I was wondering if it is because of all the technical dialogue and a lot of work with blue screens and special effects that make that type of acting different. Maybe some actors prefer this type of work, I don't know, but it does amuse and surprise me to see the same actors in different science fiction shows throughout the years.