For the writer, every genre has its quirks and its peculiar difficulties. The peculiar difficulty of science fiction is that, at least to be true to form, there must be an aspect of science that is so integral to the plot that removing it causes the entire story to collapse. (This is the Analog Magazine definition, paraphrased.)
Three of my four novels are science fiction, with the fourth being science fiction/romance.
Neanderthal Swan Song
Take away cloning and the entire story evaporates. In fact, without cloning, the entire story is this: Neanderthal body found in Greenland. Visit our museum.
Rigel Kentaurus
Without the faster-than-light theory, this is just a boring trip to explore another solar system. We collect some rocks, observe a flare, and go home. Yawn.
Fishpunk
The entire novel explores the concept of ichthyotech (fish technology). While it’s a fun concept to explore, without the fish tech, there is no story. (This novel is not yet released.)
Turn About
This novel was my NaNoWriMo 2009 project, and that shows. The first part of the novel is contrived and not very believable, which is the major reason this novel has not been published yet. It needs an overhaul, which I will probably work on come 2013.
However, I cannot think of any one technology concept that acts as lynchpin. It is an idea that holds the plot together, so it could be considered a social science fiction story, I suppose.
SF is hard (to write)
Science fiction is difficult to write, or at least, it’s difficult to write well. That tech or science lynchpin must be there, and it requires story on top of that. It’s a fun genre to work in, and one that gets an unfair share of abuse from the general public, who don’t realize that Star Wars and real science fiction are as different as a bobcat and a catfish.