Being a geneticist myself (plant geneticist, to be precise), I decide to raise the question about the Federation attitude toward genetical engineering, especially genetic modifications of sentient beings.
Traditionally, this is explained in Trekkieverse in pretty simple therms: "there were Eugenic Wars, and humans were so horrified, that they forbade almost any human modifications and presuade the whole Federation to do the same". Frankly, this is... outdated. Yes, this seemed perfectly plausible in 1960-1980s, was partially plausible in early 2000s, but with modern progress in biotechnology, this all started to look pretty much outdated. Especially considering the usual Federation quirk on self-improvement and personal potential development.
Usually to explain that, the authors tend to wave their hands and claim something like "the Federation aimed only toward natural development, and genetic engineering is unnatural"... Well, this could work in 1980s (when most of peoples have only very vague ideas, what is that biotechnology), but now it is more or less universally known, that biotechnology is perfectly "natural" (come on, the average virus preformed DNA modifications long before humankind evolved!
). Moreover, from modern positions it is almost impossible to imagine that humankind could settle other worlds without at least SOME modifications. After all, we, humans, evolved in and adapted to very specific environment - and while the variety of Earth natural conditions might seems to be pretty broad, this is nothing comparable to what humans could meet on alien worlds.
So, it seems that said element of Star Trek canon need to be... retconned a bit. Especially considering how many new planets Starfleet personnel tended to visit in casual dress - without sealed suits, oxygen tanks, filtration masks, ect., ect., ect. Unless we want to start any adventure from "doctor McCoy treated Kirk and Spock from multiple allergies, severe indigestions, death of gastric microflora after five minutes on the surface on the new M-class planet", of course - I suggest that we need to assume that the average Federation human is augmented enough to withstand at least basic environment differences.
Traditionally, this is explained in Trekkieverse in pretty simple therms: "there were Eugenic Wars, and humans were so horrified, that they forbade almost any human modifications and presuade the whole Federation to do the same". Frankly, this is... outdated. Yes, this seemed perfectly plausible in 1960-1980s, was partially plausible in early 2000s, but with modern progress in biotechnology, this all started to look pretty much outdated. Especially considering the usual Federation quirk on self-improvement and personal potential development.
Usually to explain that, the authors tend to wave their hands and claim something like "the Federation aimed only toward natural development, and genetic engineering is unnatural"... Well, this could work in 1980s (when most of peoples have only very vague ideas, what is that biotechnology), but now it is more or less universally known, that biotechnology is perfectly "natural" (come on, the average virus preformed DNA modifications long before humankind evolved!

So, it seems that said element of Star Trek canon need to be... retconned a bit. Especially considering how many new planets Starfleet personnel tended to visit in casual dress - without sealed suits, oxygen tanks, filtration masks, ect., ect., ect. Unless we want to start any adventure from "doctor McCoy treated Kirk and Spock from multiple allergies, severe indigestions, death of gastric microflora after five minutes on the surface on the new M-class planet", of course - I suggest that we need to assume that the average Federation human is augmented enough to withstand at least basic environment differences.