I think Ripley being a woman goes much further than the science fiction genre. I also think it is not contained by the bounds of fiction.

I don't think James Cameron or Quentin Tarantino would have careers without the existence of Ripley. Both write incredibly strong female characters that most likely would have been watered down if they couldn't have pointed to Ripley as an example.

SIDE NOTE: From what I've read of the various drafts, all the roles in ALIEN (Star Beast) were gender neutral. I guess, if you think that by default that means the role of Ripley was written for a man -- so be it.