The Frankenstein story is an old one: man meddles with things which should be not meddled with by man, gets burned by it. But Mary Shelly's novel did more than just attach a name to that old tale of curiosity and hubris, it also gave a name to the concept of building a human being - or something like a human being, anyway - from the ground up.
You'll see this in science fiction to a fair degree. In one SF realm, for example, career soldiers are career criminals who have been partially memory-wiped, undergone some handwavium personality reconditioning, and fitted with neural inhibitors that, at least in theory, prevent disloyalty. They also get a partial rebuild, making them stronger and tougher, and get implanted with drug injectors they (or others) can use for a temporary alteration in consciousness.
But, really, I want to look at rebuilding human beings from the genes on up, not taking ordinary people and rebuilding them. Among other things, there's less of the issue of rejection...
Two worlds of the far future, and one of the past.
Those of you who know about Battletech... well, you're terrible geeks. But never mind. I'm instead going to point out that the world of Battletech is mainly divided into two great factions: the Inner Sphere, a group of mini-empires run by various noble houses, and the Clans, descendents of a general who led his soldiers and their families out of an apocalyptic war to find peace and eventually return home to restore order - only they've become cultists, revering the leader of the Exodus as a saint, and believing in a very peculiar code of blood-purity and honor.
Why're they interesting? Well, remember what I said about building new men from the ground up? The Clans can muster military forces that are somewhat smaller but much better-trained and better-equipped than the armies fielded by the Inner Sphere's most warlike houses or their finest mercenaries. And their shock-troops, among the footslogging infantry, are not exactly human. The authors of Battletech stated that the Clans have a caste system, with five casts: in order of prestige, they are Warriors, Scientists, Merchants, Technicians and Laborers. And the warriors (pilots, armored cav crew, infantry, etc.) are subject to a strict and passionless eugenics program; a child born the usual way, from a hookup between two warriors, would be a second-class citizen, even apart from the mutations bred into the different lines of the warrior caste. Pilots tend to be small and wiry, with large eyes of a kind better suited to predatory birds; cavalrymen are perhaps the most normal, although they are selected for physical agility and reflexes; and the infantry are giants, built like masonry. And all of them are selected, at least in training for a cunning tactical intelligence.
It's the infantry I wanted to focus on, though. The authors, playing the part of the geneticists, thought about this: let us make a man who is bigger and stronger, right? Now, how would this be achieved? Too much growth hormone, or growth hormone for too long, comes with a peculiar set of side effects, like a weak heart or altered metabolic patterns. Let's rewrite that part of the genome, give the sucker a bigger heart with built-in redundancy, tweak his liver for more glycogen and his muscles for myoglobin and so on, adjust the parts dealing with fine motor control so his large fingers won't prove a liability later in life... and so on. The result is the Elemental infantry, these people of very large stature and increased toughness. Kind of weird, though, if nothing else because they are so obviously different from everyone else in the society they belong to. The same goes for the pilots. The cavalrymen would seem to have it easiest, only of course they share the same fanaticism as everyone else that prevents them from mingling. Maybe that social model of genetic engineering isn't a good one.
Let's go back to some other old-school SF, then. H. G. Wells wrote The Island of Dr. Moreau, which tells the tale of a physiologist banished from Britain because of the cruelties inflicted on animals in the course of his research. It is narrated by a wealthy fellow who gets shipwrecked and ends up on the Island, where he witnesses this and that, most notably that Dr. Moreau is trying to study the physiology of animals and the ways in which it can be manipulated in a stable and persistent manner. He uses surgery and religion to turn animals into people, although he can never completely erase the bestial origins of his subjects from their fundamental appetites. Eventually, of course, Moreau's hubris destroys him. And, really, who can object? He was pretty much the worst character in the story; his subjects might be gratuitously violent, but (says Wells), what else can we expect from beasts? But Moreau and his aide are human beings and should be expected to behave with more compassion. Excellent story, "Hebrew noses" and all (my nose, however, knows Yiddish).
Now, Dr. Moreau was adopted more recently, in the early 1990s, by an author who started from the point of view that the USA would within a decade become isolationist, and thereby be insulated from the troubles of the rest of the world; he posited that within the first few decades of the 21st century, international political tensions would drive much of the world into a frenzy of military R&D. In the timeline he included in one of his novels, it all started with a South Korean science team working with dogs, trying to alter their genes to produce dogs smart enough, trainable enough and with keen enough senses to either clear minefields or plant them. From there, it spread, some brilliant if ethically compromised researcher deciding that his country really needed a soldier, or a scientist, or an engineer, who was as smart and capable as a human being, but would be better at job-specific tasks like, say, tracking through trackless wilderness, fighting in squads, seeing in the dark without the need for batteries, being ridiculously strong, being able to go places undetected, being able to manipulate databases with the greatest of ease... whatever.
So, goes the story, the engineer took a representative human genome and started editing it, cutting and pasting sequences from other species that had the appropriate traits. For example, the pack behavior and superior scenting and hearing ability of dogs; the curiosity, hardiness and fast generation cycle of rats; the viciousness of foxes, the keen night-vision of cats, and so on. But because his splicing technique wasn't perfect, he ended up adding... side effects. Altered development of the skin to produce a coat, rather than the normal human pattern of patchy fuzz. A tendency toward flightiness, if the genes were borrowed from a small prey species. Spurts of uncontrollable aggression - berserker syndrome, if you will. A certain slowness and thoroughness of thinking, utter unflappability along with the intended ability to heft hundreds of pounds or drive a fist through masonry without breaking a sweat. Sometimes, along with increased strength and tendency toward aggression comes utter stupidity or - whoops! - claws. Sometimes heightened intelligence comes with a tendency toward frailty. Sometimes night vision comes with strange and inhuman eyes.
Thus, wrote the author (who uses the pseudonym S. Andrew Swann), were the inhuman soldiers who would fight in the Pan-Asian war, and afterward become second-class citizens in most of the world, created. The four novels in this series are meditations on racial tension, social injustice and the human tendency to solve problems with violence. The first, third and fourth books have moderately interesting characters as protagonists (Nohar and Angelica, not really important), but they're not as interesting in that they're obviously the products of genetic engineering, as in, you could spot them as not exactly human from a block away. They get along because they're civil enough to deal with humans and, since they're obviously not human, they get along with fellow members of their disadvantaged social group. The second novel in the series focuses on someone who looks pretty much human, except for her yellow, catlike eyes (and the character wears sunglasses most of the time). As she looks mostly human, but isn't wholly so, she doesn't fit into either category; where other people might be like fish swimming in a social ocean, she's mostly beached.
I bet the technicians hadn't seen that coming either.
It looks like the trouble with creating Homo sapiens superior is that you end up with people who can't really fit in. They do the jobs they were designed to do, sure, but that reduces them merely to being tools - we object to that so strenuously when we see it in, let's say, American foreign policy and treatment of its soldiers. It seems plainly unethical, really, to create a thinking, feeling being, in order to treat it like property and then discard it once its utility is fulfilled or obsolete, leaving it nowhere to be accepted among equals.
What say you?
(Other diaries in this series include essays on nanopower, a drug contraindication database, novel prosthetics, virtual worlds, robot safety, ye short fiction, the sociology of fictional places, steam-powered giant robots, thermal depolymerization, nuclear airplanes, psychic powers, transgenic bacteria that make useful compounds, lightning in a jar, neural interfaces, powered armor, sonic weapons, rapid prototyping, putting Mentos and Diet Coke to good use, life on life support, combining farming and electrical generation, pigeon pilots, cuttlefish behind the wheel, the hafnium bomb, and building a better skunk. Don't read these if you value preserving an unwarped mind.)