In the late 20th-early 21st centuries the term has been promoted by and associated with fiction by Margaret Atwood (The Handmaid's Tale, 1985; Oryx and Crake, 2003; Maddaddam trilogy 2003-2014) that show similarities and differences with traditional science fiction.
similarities to standard science fiction:
extrapolations* (extensions) from current technological and demographic trends. [*to extrapolate: To apply (a theory, etc.) to unknown situations on the basis of its relevance to known situations; to infer (conclusions) from known facts or observed tendencies (Oxford English Dictionary)]
differences from standard science fiction:
(Standard science fiction is often criticized for simplistic suspense-and-showdown plots and retro gender characterizations, with its politics limited to innocent, noble young people resisting corrupt old tyrants. Exceptions abound, but because science fiction becomes outdated so quickly, the influence of literary classics in the field is limited.)
1953 R. A. Heinlein in Library Jrnl. July 1188/1 The term ‘speculative fiction’ may be defined negatively as being fiction about things that have not happened.
1978 N.Y. Times 30 Mar. c22/3 A 10-part series based on what Mr. Kotlowitz called ‘speculative fiction’, stories that go beyond sci-fi and deal with ‘ethical and moral demands’ made in new worlds to come.
Critical Sources (from Mari Caylor's 20 June2013 Web Review):