Genetic Engineering and Cloning
Genetic engineering and cloning are popular topics in science fiction. They were featured several times in Star Trek, with a focus either on the dangers of "playing god" in general and on the rightfulness of such a procedure, or on the subjects or victims in particular. This article sorts out the available evidence, points out inconsistent statements and attempts to outline a general trend of how Star Trek deals with the topic.
TOS: Space Seed
The impression is created that genetically improved humans have an intrinsic ambition to rule over naturally gifted humans. Overall, the criticism about genetic engineering in the episode is quite concrete. Rather than a general condemnation of tampering with human DNA, the result is criticized here: Genetic engineering, although it might be tempting to improve humanity, goes along with bad side effects and creates criminals. Only Lt. Marla McGiver, who falls in love with Khan, is positive about Khan's nature, but she is rather love-sick than providing a rational view on genetic engineering.
TNG: Unnatural Selection
The practice of these scientists is comparable to that of the creators of Khan, maybe worse. But no one of the Enterprise crew decidedly condemns the irresponsible and inhumane experiments, which we would expect to be outlawed, even if certain mild forms of genetic engineering were legal in the Federation (which they aren't, as we will learn in DS9: "Dr. Bashir, I Presume?"). Captain Picard and most of the rest are at most skeptical, and Dr. Pulaski is even fascinated by the idea of breeding humans without illnesses and with all kinds of funny features.
TNG: Up the Long Ladder
It is true that Riker's and Pulaski's right of individuality and of integrity, as it is almost certainly granted by Federation laws and probably stated in the constitution, has been violated. Nevertheless, killing one's clone can well be regarded as an act of murder, no matter if the clones are still developing, are not yet "programmed" and therefore not yet self-aware - and no matter whether cloning is legal or not. Especially Pulaski's stance is peculiar, bearing in mind how she was still rather positive about the bred über-children in "Unnatural Selection". In retrospect, she was either overly hypocritical about genetic engineering as a general concept, or just overly selfish when it came to her personal rights.
TNG: The Hunted
Genetically enhanced soldiers appear in TNG: "The Hunted". They were designed by the Angosians to be the ultimate soldiers with supernatural abilities, and they were never meant to be integrated into the Angosian society. Picard condemns the practice of breeding soldiers, but ultimately it is once again mostly the unfortunate result of genetic engineering and not the practice itself that is in the focus of interest, as the soldiers are trying to take over the planet. Still, there is a reconciling tone in the end when it becomes obvious that the super-soldiers are not intrinsically bad and that there may be a peaceful solution of the conflict.
TNG: The Masterpiece Society
But the focus of attention shifts in the following, when it becomes clear that the alleged paradise has been contaminated. It turns into one of the many episodes that revolves around the Prime Directive, even though it purportedly wouldn't apply here because the settlers are human. In the eyes of the colonist Martin, disturbing the colony's genetic balance by letting some of the colonists leave is even worse than its destruction. This is clearly hypocritical, because the colony would hardly need a genetic balance if all were doomed to die, as Worf and Riker correctly object, but even Picard acknowledges that a paradise is being destroyed. Still, Picard's stance does not really touch the issue whether genetic engineering is wrong or right. Picard merely acknowledges that, irrespective of its inception, this colony has developed its own characteristics, its own culture that deserves to be preserved.
DS9: A Man Alone
The episode creates the impression that cloning is anything but commonplace, although the technology is rather well-known. The ethical impact of cloning is not really discussed, as it is just an aspect of a murder mystery here. Yet, we learn that killing one's clone is punishable as murder under Bajoran law (as opposed to the Federation, thinking of what Riker did in TNG: "Up the Long Ladder"). It is mentioned only in a side note that the clone of Ibudan that Bashir created in this episode is kept alive and is allowed to conduct a normal life. We don't learn far he was developed in the end, how he would gain the necessary knowledge and experience and whether Bashir has a bad conscience for playing god, even if it was unwittingly.
The Vorta are another race created by the Founders. If we believe Weyoun (who may have told Odo a lot of crap in DS9: "Treachery, Faith and the Great River" though), they have been developed from a primitive ape-like race and are reproduced by cloning. Damar, Worf and Garak obviously had no bad conscience killing various Weyoun clones. But we shouldn't assume that the life of a clone was of lower value to them. Rather than that, it was made easy because of the many crimes that Weyoun was responsible for, of a kind that could have been committed by a "natural" lifeform just as well.
DS9: Dr. Bashir, I Presume?
Whilst this is not necessarily inconsistent with previous episodes, it lets appear the experiments in TNG: "Unnatural Selection" in an even worse light. If as little as the improvement of young Julian's abilities is illegal (and will get his father into prison for two years), what about the irresponsible experiments of the scientists on Gagarin IV? Not only should Picard have been disgusted, but it would have been his duty to put all the scientists under arrest for their criminal activities.
The case of Bashir's parents, on the other hand, may be understandable to a certain extent. As it is mentioned in the episode, Richard Bashir was frequently switching jobs, and he was obviously never really successful in and content with his life. No one needs to be poor or underprivileged in the 24th century, but with all the wealth and social security it may be still important to have certain capabilities for personal happiness - and to improve oneself, as Picard would put it. When the Bashirs saw that their son's abilities were below average, they decided to change that. Although the result is clearly unnatural, Julian is quite different from any genetically enhanced human being shown so far. It wasn't even noticed by anyone until he was forced to admit it in "Dr. Bashir, I presume" (although, in retrospect, there is almost no way to explain why he didn't make use of his improved senses in one emergency or another).
The "Jack Pack"
VOY: Child's Play
Cloning is mentioned only as a humorous side note. The Borg twins wanted to clone Naomi for a science project, as Seven said, but she suggested they should start with something smaller. So they went with potatoes.
Star Trek Nemesis
Picard is very negative about cloning, but this may have to do with he himself being the victim of the procedure, like Riker already in "Up the Long Ladder". Moreover, Shinzon, the clone, turns out to be an unstable person who is out for destruction and conquest, much like Khan. Yet, Shinzon claims that he and Picard are genetically identical and that, under the same dire circumstances, Picard may have become a villain just like him. In this light, the story is inconclusive. It shows all the usual clichés about genetic engineering in Shinzon's agenda and actions, only to put them into perspective verbally.
The Suliban, or at least a faction known as the Cabal, are shown as a race obsessed with improving themselves through genetic enhancements. When Dr. Phlox discovers the genetic tampering in ENT: "Broken Bow", it is a reason for astonishment but not necessarily for condemnation. With the Suliban's elasticity being an opportunity to play with CGI, it is only a side aspect anyway in the pilot episode and the following Suliban arc. Their motivation is not further elucidated or only commented on.
Cloning, like any kind of genetic tampering, has been almost consistently condemned for several reasons in Star Trek so far. But the discussion usually boiled down to practical and rather superficial questions of cloning. Moreover the clones themselves, just like various other types of doppelgangers, were depicted as threatening, like in TNG: "Up the Long Ladder" or DS9: "A Man Alone". This one-sided impression is eventually corrected in "Similitude" by letting the clone speak for himself. But the basic question is still which person would "deserve" to live, if the chances of survival are about equal. So the possible ethical failure in "Similitude" may not have been cloning Sim in the first place, but rather consciously killing him, even if this was the original intention. In this light Sim's remark that he was meant to die just like Trip was meant to be an engineer and Archer a captain leaves a bad taste. It sounds like false heroism out of a false sense of duty, and this is unfortunately bolstered by Archer's speech at the funeral.
With the exception of the unfortunate Smike, who is arguably different, the Enterprise-style Augments are not given a chance to show any positive facet. The honor of being a criminal who shows remorse goes to Soong but not to any of them.
"Star Trek Into Darkness" radically re-imagines the character of Khan, who now is not only ethnically different but also (as a 20th century creation!) possesses blood that can resurrect the dead. Other than that, the new Khan is a vengeful villain, similar to the original one.
Summarizing, Star Trek remains somewhat consistent with its negative stance on genetic engineering and cloning. We could also take into account several more cases in which the DNA of crew members is modified on purpose, but this is usually to repair mutations, like in TNG: "Rascals" or TNG: "Genesis". The DNA fusion of VOY: "Tuvix" and its reversal is still another case that deserves to be scrutinized separately. Among the above "genetic enhancement" episodes most of all TNG: "Unnatural Selection" leaves a bad taste, because it fails to condemn the most blatant and most ruthless form of genetic engineering.
Overall, it is a disappointment that in the majority of all episodes and movies mainly the result of genetic engineering is subject to controversies instead of the procedure itself and the motivation for it. That way, the focus shifts away from the general question if humankind should be allowed to play god, and if only to remove some deficiencies that may occur with natural conception. Only "Dr. Bashir, I Presume" and "Lineage" attempt to get to the bottom of this question. Unlike Bashir himself, his four genetically enhanced friends fit into the perpetuated cliché again: that there is something intrinsically wrong with enhanced persons, and that the public needs to be protected from them.
It is also sad that in most episodes that feature genetically enhancements the subjects are either conceded a minor role or are depicted as villains like Khan. But ENT: "Similitude" successfully corrects this cliché by showing Sim, Trip's clone, as a human being and not only as a subject that the crew has to deal with.
Thanks to Bob Lemiszki for reminding me of VOY: "Lineage".