n. An imagined species that will evolve from human beings by manipulating their genetic makeup and augmenting their bodies with robotics and other technology; the future era of this species.
Also Seen As
Other Forms
The future that germline genetic engineering could enable is one of a ruling genetic caste and ultimate alienation of ourselves from ourselves. The threat from nanobotics is not just the emergence of posthumans but the wholesale replacement of the human, genetically altered and otherwise.
—Ralph Brave, “Germline warfare,” The Nation, April 07, 2003
Messing with the boundaries between man and machine, Data is an emblem for the festival of the posthuman. Because, like Data, artificial life forms from Frankenstein's monster onwards are impelled by familiarly human desires.
—Annemarie Jonson, “Unnatural urges,” Sydney Morning Herald (Australia), March 22, 2003
1971 (earliest)
Clay senses, as he has never before sensed, the full span of time through which he has passed; for now he is caught in a sea of shapes, prehuman and human and posthuman, coming and going, smothering him, demanding comfort from him, seeking redemption, chattering, laughing, weeping.
—Robert Silverberg, “Son of Man,” Ballantine, January 01, 1971
What is this germline genetic engineering that's mentioned in the example citation? It's one of the two main ways that scientists are proposing to alter humans at the genetic level. The first method is called somatic gene therapy, and it involves injecting foreign genetic material into a person in the hope that the person's cells will take up that DNA. If successful, that person's cells will then start producing whatever proteins the DNA's gene or genes are meant to express. (Or they may stop producing certain proteins, such as those that cause the symptoms of a disease.)

The second method involves altering the existing genes of a fertilized egg. Such an egg is called a "germ" cell, so this method is known as "germline" genetic engineering.

The path to a posthuman world does not go through somatic gene therapy since that technique (which is already in clinical trials) only works on individuals: the genetic modifications are not passed on to the person's offspring. Germline tinkering, on the other hand, modifies the person's genetic makeup, and that makeup gets passed on to all of that person's descendants. Make enough modifications — vastly improved hearing, strength, endurance, and so on — and the result is a species that perhaps ought to be classified as something other than homo sapiens. (Particularly when you "augment" this genetic mutant with robotics and internal nano-machines designed to keep disease and physical obsolescence at bay.)

Thanks to Mike Christie for providing me with the earliest citation for this word.