Biology is outside of my range of expertise. Of course, like most people I studied it in limited amounts in my early years in college and a high school class. Here is an article I’m able to write it because of what I know from Star Trek—genetic engineering and eugenics.
The concept of genetic engineering actually goes back further than most people realize on Earth when humanity began to domesticate animals for labor or food. Humans began to breed desired traits into said animals and food in order to better the amount of grain produced, milk able to be given, or amount of muscle tissue developed in a short time. By the Industrial Revolution, animals commonly used by mankind would not resemble their wild ancestors except on the basic level. Dogs are the best example of this kind of breeding.
Plant or animal husbandry is genetic engineering just on a slower scale. It is still liable for random chance to intercede and produce offspring that may not have said traits. Now, apply these ideas to human beings themselves and you get eugenics. Eugenics in history has a very negative connection to Nazi Germany. So instead of writing a whole few thousand words on how evil it can be when applied to self-aware human beings, I will leave the reader to look up what information they wish to on this dark subject.
But Eugenics also ties into Star Trek with the Eugenics Wars and the Augments. Genetically superior humans bred to be smarter, stronger, and faster. We can assume—with how effective the end product was in the mid-1990’s—that the eugenic experiments of World War 2 continued in some capacity after the end of that conflict.
Regardless, the experimentation on human beings to make Augments left such a deep impression on humanity’s psyche that even in the mid-22nd century the memory of the Augments still had humans feel revulsion. This same deep fear and pain across the planet would influence the Federation and lead to a ban on genetic engineering we see in The Original Series. This same ban would seem to fade by the time of The Next Generation.
I remember watching the episode Unnatural Selection and being shocked that Federation scientists would have engineering humans to develop into full adults so quickly, along with improving so much more about them including giving them telepathy! This episode is problematic to say the least as future episodes, mostly in Deep Space Nine involving Doctor Bashir.
Doctor Bashir isn’t just problematic because he’s an Augment. It’s also that it’s said that the Federation allows genetic engineering to fix genetic flaws or to allow a person to operate normally as long as it doesn’t make them ‘better’. Why is this problematic?
Define what a genetic flaw is. Could, culturally, a planet say that all people must have blond hair and blue eyes? These do not improve a human. They just fix what that society says is a problem. Take this to the logical extreme that another TV show did. What about gender?
Another path for this to take is a Federation colony group wanting to colonize a world entirely covered in oceans. Would genetically altering humans to have gills and webbed fingers be considered an augmentation if it would disadvantage them outside of their watery environment?
Would it not be logical for a group of Vulcans wanting to colonize a world orbiting close to a red dwarf star prone to flares to modify their genome to make their skin as dark as possible to absorb radiation before it would damage more important cells inside? Maybe changing their skin to be as light as possible to reflect the radiation? Maybe even choosing to adjust their eyes to see in the redshifted spectrum provided by that star
These ideas alone are fodder enough for a whole series of adventures. A player may wish to make a character that came from one of these newer colonies of the 24th century where genetic changes were allowed as long as they did not ‘augment’ the person. Maybe an Andorian character has come from a long line of asteroid miners with longer fingers and toes that help them grasp rungs to move around in microgravity. Perhaps a character wants to play a smooth-headed Klingon from a world now a member of the Federation, genetically modified from ‘normal’ Klingons and with slightly different internal organs.
A gamemaster may also wish to have an adventure dealing with how the Federation is handling the admission of a colony world that has adapted themselves too much to their environment and barely resemble their original forms. Humans with green skin for photosynthesis, Andorians with gills, Tellerites with huge barrel chests with three sets of lungs to allow them to breathe in air that was thin enough to kill them in seconds otherwise.
How do you do diplomacy with a species that believes that the species of the Federation are nothing more than animals because they do not give birth to children with only green eyes and enforce their own type of eugenics on worlds they conquer, murdering those they see as nothing more than weak chattel and ‘uplifting’ the animals into the true personhood of being green-eyed?
These seem like petty and silly examples, but these sorts of plots can quickly become dark and hard-hitting to those of us that knew people directly impacted by such ideals or if we were impacted ourselves.
Perhaps the real reason the Federation limits such genetic tinkering is to ensure that the member races it represents don’t become thousands of splintered sub-species over time, quickly becoming niche and too entrenched in their own environment to otherwise interact with the rest. Perhaps it’s just because the writers and producers don’t want to have to explain that the fishman featured next week is actually a human being just like the standard humans we see.
The reasons are up to you in your game. Explore them and see if they fit in your own vision!